Service Manual

Variable Displacement Pumps
MP1

www.danfoss.com

Service Manual
MP1

Revision history

2 | © Danfoss | August 2024

Table of revisions
Date

ChangedRev

August 2024

Minor corrections to P400738 on MDC Neutral Adjust and G020/G025 on MP1 plug size andtorque0405

January 2024

Minor corrections

0404

December 2021 Added HDC control

0401

October 2021

Added MDC Neutral Adjust, added notes on MP1 Charge Pump Inspection

0306

April 2021

Changed document number from 'AX00000244' to 'AX179786484978' and correctedinterface with ECU (EDC) graphic

0305

November 2019 updated minor errors

0203

October 2019

Added automotive controls information

0202

April 2019

Updated for new control types

0201

October 2018

Corred sort strings on MDC and additional options to MDC illustration

0107

January 2018

update control current table

0106

November 2017 Add NFPE

0105

October 2017

Remove HDC

0104

July 2017

update ports and plugs

0103

April 2017

Add HDC

0102

August 2016

First edition

0101

AX179786484978en-000405

Service Manual
MP1
Contents
Introduction
Hydrostatics Servicing Overview................................................................................................................................................ 6
General instructions........................................................................................................................................................................ 6
Remove the unit.......................................................................................................................................................................... 6
Lubricate moving parts.............................................................................................................................................................6
Replace all O-rings and gaskets............................................................................................................................................. 6
Safety Precautions............................................................................................................................................................................7
Unintended machine movement..........................................................................................................................................7
Flammable cleaning solvents................................................................................................................................................. 7
Fluid Under Pressure..................................................................................................................................................................7
Personal safety............................................................................................................................................................................. 7
Symbols used in Danfoss literature............................................................................................................................................8
Technical specifications
MP1 design specifications.............................................................................................................................................................9MP1 technical data...........................................................................................................................................................................9MP1 operating parameters.........................................................................................................................................................10
MP1 fluid specifications...............................................................................................................................................................10
Operation
High Pressure Relief Valve (HPRV) and charge check....................................................................................................... 11
Bypass function...............................................................................................................................................................................11
Charge Pressure Relief Valve (CPRV)....................................................................................................................................... 12
Loop flushing valve....................................................................................................................................................................... 13
Electrical displacement control (EDC).................................................................................................................................... 14
EDC principle..............................................................................................................................................................................14
EDC operation............................................................................................................................................................................14
Control signal requirements, EDC MP1............................................................................................................................ 15
EDC solenoid data.................................................................................................................................................................... 15
Control response.......................................................................................................................................................................16
EDC response time..............................................................................................................................................................16
Manual override (MOR)...........................................................................................................................................................16
Hydraulic displacement control (HDC).................................................................................................................................. 18
HDC principle............................................................................................................................................................................. 18
HDC operation........................................................................................................................................................................... 18
Hydraulic signal pressure range..........................................................................................................................................19
Pump output flow direction vs. control pressure......................................................................................................... 19
Control response.......................................................................................................................................................................19
Response time, HDC................................................................................................................................................................ 20
Swashplate angle sensor for EDC controls........................................................................................................................... 21
Swash plate angle sensor parameters (EDC).................................................................................................................. 21
Swash plate angle sensor connector.................................................................................................................................22
Interface with ECU (EDC)........................................................................................................................................................22
Manual displacement control (MDC)......................................................................................................................................22
MDC principle............................................................................................................................................................................ 22
MDC operation.......................................................................................................................................................................... 24
MDC shaft rotation...................................................................................................................................................................24
Control response.......................................................................................................................................................................25
MDC response time............................................................................................................................................................ 25
Neutral start switch (NSS)...................................................................................................................................................... 25
Case gauge port M14.............................................................................................................................................................. 26
Lever..............................................................................................................................................................................................27
Forward-neutral-reverse electic control (FNR).................................................................................................................... 27
FNR principle.............................................................................................................................................................................. 27
Control response.......................................................................................................................................................................29
Response time, FNR............................................................................................................................................................30
Non feedback proportional electric control (NFPE).......................................................................................................... 30
Control signal requirements.................................................................................................................................................31
Control response.......................................................................................................................................................................32
Response time...................................................................................................................................................................... 32© Danfoss | August 2024

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Service Manual
MP1
Contents
Non-feedback, proportional hydraulic control (NFPH).................................................................................................... 32
Control response.......................................................................................................................................................................33
Response time...................................................................................................................................................................... 34
Automotive control (AC)............................................................................................................................................................. 34
Control-cut-off valve (CCO valve).............................................................................................................................................37
CCO solenoid data....................................................................................................................................................................38
Brake gauge port with MDC................................................................................................................................................. 39
Displacement limiter.....................................................................................................................................................................39
Displacement change (approximate)................................................................................................................................39
Speed sensor................................................................................................................................................................................... 40
Temperature Range................................................................................................................................................................. 40
Output pulses.............................................................................................................................................................................40
Mating connectors................................................................................................................................................................... 40
Speed sensor 4.5 – 8 V............................................................................................................................................................ 40
Temperature Signal.......................................................................................................................................................................41
Operating parameters
Input speed...................................................................................................................................................................................... 42
System Pressure..............................................................................................................................................................................42
Charge pressure..............................................................................................................................................................................43
Charge pump inlet pressure...................................................................................................................................................... 43
Case pressure...................................................................................................................................................................................43
Temperature.................................................................................................................................................................................... 43
Viscosity.............................................................................................................................................................................................44
Fluid and filter maintenanceFiltration system ............................................................................................................................................................................ 45
Pressures measurements
MP1 port locations and gauge installation...........................................................................................................................46
Initial startup procedure
General ..............................................................................................................................................................................................48
MP1 start-up procedure...............................................................................................................................................................48
Troubleshooting
Overview........................................................................................................................................................................................... 50
Safety precautions......................................................................................................................................................................... 50
Electrical troubleshooting.......................................................................................................................................................... 50
System Operating Hot..................................................................................................................................................................50
Transmission Operates Normally in One Direction Only.................................................................................................51
System Does Not Operate in Either Direction..................................................................................................................... 51
System noise or vibration........................................................................................................................................................... 52
Neutral Difficult or Impossible to Find................................................................................................................................... 52
Sluggish System Response......................................................................................................................................................... 52
Adjustments
Pump adjustment.......................................................................................................................................................................... 53
Standard Procedures.................................................................................................................................................................... 53
Charge Pressure Relief Valve......................................................................................................................................................54
Displacement Limiter................................................................................................................................................................... 55
EDC/HDC Neutral Adjustment.................................................................................................................................................. 56
MDC Neutral Adjust...................................................................................................................................................................... 58
Mechanical/Hydraulic Neutral Adjustment..........................................................................................................................59
Servo Adjustment.....................................................................................................................................................................59
Verify neutral setting............................................................................................................................................................... 59
Servo Adjustment Side M4....................................................................................................................................................60
Minor repair
MP1 standard procedures and pump removal................................................................................................................... 61
EDC/HDC Control........................................................................................................................................................................... 61
MP1 EDC/HDC control removal...........................................................................................................................................61
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MP1
Contents
Controls inspection..................................................................................................................................................................62
MP1 EDC/HDC control assembly.........................................................................................................................................62
MP1 control solenoids/actuator housing replacement................................................................................................... 64
MDC Control.................................................................................................................................................................................... 65
MP1 MDC control removal.................................................................................................................................................... 65
MDC Illustration................................................................................................................................................................... 65
MDC Legend......................................................................................................................................................................... 66
Controls inspection..................................................................................................................................................................66
MDC Control Assembly...........................................................................................................................................................66
Automotive control.......................................................................................................................................................................68
Automotive control removal................................................................................................................................................ 68
Controls inspection..................................................................................................................................................................69
Automotive control installation.......................................................................................................................................... 69
Charge Pump...................................................................................................................................................................................71
MP1 charge pump removal.................................................................................................................................................. 71
MP1 charge pump inspection..............................................................................................................................................72
MP1 charge pump assembly................................................................................................................................................ 72
High Pressure Releif Valve (HPRV)............................................................................................................................................73
MP1 HPRV valve removal.......................................................................................................................................................73
HPRV valve inspection............................................................................................................................................................ 73
HPRV Valve Reassembly......................................................................................................................................................... 73
Charge Pressure Relief Valve (CPRV)....................................................................................................................................... 74
MP1 CPRV removal...................................................................................................................................................................74
CPRV inspection........................................................................................................................................................................ 74
MP1 CPRV assembly.................................................................................................................................................................74
MP1 loop flushing removal (28/32 pictured)....................................................................................................................... 75
MP1 loop flushing spool inspection.................................................................................................................................. 76
Reassembly................................................................................................................................................................................. 76
Shaft Removal................................................................................................................................................................................. 76
Inspection....................................................................................................................................................................................77
Shaft Reassembly......................................................................................................................................................................77
Fastener size and torque chart
Fastener size and torque............................................................................................................................................................. 78
MP1 plug size and torque........................................................................................................................................................... 79© Danfoss | August 2024

AX179786484978en-000405 | 5Service Manual
MP1
Introduction
Hydrostatics Servicing Overview
This manual includes information on installation, maintenance, and minor repair of the . It includes a
description of the unit and its individual components, troubleshooting information, and minor repair
procedures.
Performing minor repairs may require the unit to be removed from the vehicle/machine. Thoroughly
clean the unit before beginning maintenance or repair activities. Since dirt and contamination are thegreatest enemies of any type of hydraulic equipment, follow cleanliness requirements strictly. This isespecially important when changing the system filter and when removing hoses or plumbing.
A worldwide network of Danfoss Global Service Partners is available for major repairs. Danfoss trains andcertifies Global Service Partners on a regular basis. You can locate your nearest Global Service Partner
using the distributor locator at http://www.danfoss.com.
For detailed technical information about the , please see the relevant technical information document.
Attention
Major repairs requiring the removal of a unit’s center section, servo sleeves, or front flange voids thewarranty unless a Danfoss Authorized Service Center performs them.
General instructions
Remove the unit
If necessary, remove the unit from the vehicle/machine. Chock the wheels on the vehicle or lock themechanism to inhibit movement. Be aware that hydraulic fluid may be under high pressure and/or hot.
Inspect the outside of the pump and fittings for damage. Cap hoses after removal to prevent
contamination.
Keep it clean

Cleanliness is a primary means of assuring satisfactory pump life, on either new or repaired units. Clean
the outside of the pump thoroughly before disassembly. Take care to avoid contamination of the system
ports. Cleaning parts by using a clean solvent wash and air drying is usually adequate.
As with any precision equipment, keep all parts free of foreign materials and chemicals. Protect all
exposed sealing surfaces and open cavities from damage and foreign material. If left unattended, cover
the pump with a protective layer of plastic.
Lubricate moving parts

During assembly, coat all moving parts with clean hydraulic fluid. This assures that these parts arelubricated during start-up.
Replace all O-rings and gaskets

Danfoss recommends that you replace all O-rings, seals and gaskets. Lightly lubricate all O-rings withclean petroleum jelly prior to assembly.
Secure the unit

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Service Manual
MP1
Introduction
For repair, place the unit in a stable position with the shaft pointing downward. It will be necessary tosecure the pump while removing and torquing end covers, controls, and valves.
Safety Precautions
Always consider safety precautions before beginning a service procedure. Protect yourself and othersfrom injury. Take the following general precautions whenever servicing a hydraulic system.
Unintended machine movement
Unintended movement of the machine or mechanism may cause injury to the technician or bystanders.
Secure the machine or disable/disconnect the mechanism while servicing to protect against unintended
movement.
Flammable cleaning solvents
Some cleaning solvents are flammable.
Do not use cleaning solvents in an area where a source of ignition may be present to avoid possible fire.
Fluid Under Pressure
Escaping hydraulic fluid under pressure can have sufficient force to penetrate your skin causing serious
injury and/or infection. This fluid may also be hot enough to cause burns.
Relieve pressure in the system before removing hoses, fittings, gauges, or components. Never use yourhand or any other body part to check for leaks in a pressurized line. Use caution when dealing withhydraulic fluid under pressure. Seek medical attention immediately if you are cut by hydraulic fluid.
Personal safety
Protect yourself from injury whenever servicing a hydraulic system.
Use proper safety equipment, including safety glasses, at all times.
Hazardous material
Hydraulic fluid contains hazardous material.
Avoid prolonged contact with hydraulic fluid. Always dispose of used hydraulic fluid according to state,
and federal environmental regulations.

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Service Manual
MP1
Introduction
Symbols used in Danfoss literature
WARNING may result in injury

Tip, helpful suggestion

CAUTION may result in damage to product orproperty

Lubricate with hydraulic fluid

Reusable part

Apply grease / petroleum jelly

Non-reusable part, use a new part

Apply locking compoundNon-removable item

Inspect for wear or damage

Option - either part may exist

Clean area or part

Superseded - parts are not interchangeable

Be careful not to scratch or damage

Measurement required

Note correct orientation

Flatness specification

Mark orientation for reinstallation

Parallelism specification

Torque specification

External hex head

Press in - press fit

Internal hex head

Pull out with tool – press fit

Torx head

Cover splines with installation sleeve

O-ring boss port

Pressure measurement/gauge location or
specification

The symbols above appear in the illustrations and text of this manual. They are intended to communicate
helpful information at the point where it is most useful to the reader. In most instances, the appearanceof the symbol itself denotes its meaning. The legend above defines each symbol and explains its purpose.

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Service Manual
MP1
Technical specifications
MP1 design specifications
Features

MP1

DesignAxial piston pump with variable displacement using compact servo piston control.

Direction of input rotation

Clockwise or counterclockwise

Recommended installation position

Pump installation position is discretionary, however the recommended control position is
on the top or at the side with the top position preferred. If the pump is installed with thecontrol at the bottom, flushing flow must be provided through port M14 located on the
EDC, HDC, FNR, NFPE, NFPH, AC-1, AC-2 and MDC control. Vertical input shaft installation is
acceptable. The housing must always be filled with hydraulic fluid. Recommended
mounting for a multiple pump stack is to arrange the highest power flow towards the
input source. Consult Danfoss for non-conformance to these guidelines.

Filtration configuration

Suction or charge pressure filtration

MP1 technical data
Feature

28

32

38

45

Displacement (cm3/rev [in3/rev])28.0 [1.71]

31.8 [1.94]

38.0 [2.32]

45.1 [2.75]

Flow at rated (continuous) speed (l/min [US gal/min])95.3 [25.2]

108.1 [28.5]

125.3 [33.1]

149.5 [39.5]

Torque at maximum displacement (N•m/bar [lbf•in/1000psi])

0.45 [272.0]

0.51 [308.9]

0.60 [369.1]

0.72 [438.1]

Mass moment of inertia of rotating components (kg•m2 [slug•ft2])

0.0020 [0.0015]

0.0030 [0.0022]

Mass (kg [lb])29.6 [65.3]

38 [83.8]

Oil volume (liter [US gal])

1.5 [0.40]

2.0 [0.53]

Mounting flange

ISO 3019-1 flange 101-2 (SAE B)

Input shaft outer diameter, splines and tapered shafts

ISO 3019-1, outer Ø22mm - 4 (SAE B, 13 teeth)
ISO 3019-1, outer Ø25mm - 4 (SAE B-B, 15 teeth)

ISO 3019-1, outer Ø22mm - 1 (StraightKey)

Auxiliary mounting flange with metric fasteners, shaft outer diameterand splines

ISO 3019-1, outer Ø31mm - 4 (19 teeth)
ISO 3019-1, outer Ø25mm - 4 (StraightKey)
ISO 3019-1, outer Ø25mm -3 (Conicalkeyed, taper 1:8)

ISO 3019-1, flange 82-2, outer Ø16mm - 4 (SAE A, 9 teeth)
ISO 3019-1, flange 82-2, outer Ø19mm - 4 (SAE A, 11 teeth)
ISO 3019-1, flange 101-2, outer Ø22mm - 4 (SAE B, 13 teeth)
ISO 3019-1, flange 101-2, outer Ø25mm - 4 (SAE B-B, 15 teeth)
ISO 11926-1 - 1 1/16 - 12 (Inch O-ringboss)

Main port configuration A, B
ISO 6149-1, M27x2 (Metric o-ring boss)

ISO 11926-1 - 1 5/16 - 12 (Inch O-ringboss)
ISO 6162, Ø19mm, (Split flange boss,
M10x1.5)
ISO 6149-1 - M33x2 (Metric O-ringboss)

Case drain ports L1, L2

ISO 11926-1, 1 1/16 -12 (Inch O-ring boss)
ISO 6149-1, M27x2 (Metric O-ring boss)

Suction ports S

ISO 11926-1 - 1 1/16-12 (Inch O-ringboss)
ISO 6149-1 - M27x2 (Metric O-ringboss)

Other ports

ISO 11926-1, (Inch O-ring boss)
ISO 6149 -1, (Metric O-ring boss)

Customer interface threads

Metric fasteners© Danfoss | August 2024

ISO 11926-1 - 1 5/16-12 (Inch O-ringboss)
ISO 6149-1 - M33x2 (Metric O-ringboss)

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Service Manual
MP1
Technical specifications
MP1 operating parameters
Features
Input speed

System pressure

Units
Minimum1

28/32

min-1 (rpm)

38/45

500

500

Rated

3400

3300

Maximum

4000

3900

350 [5000]

350 [5000]

Maximum pressure

Maximum working pressure

bar [psi]

380 [5429]

380 [5429]

Minimum low loop (above case)

10 [143]

10 [143]

Charge pressure (minimum)

bar [psi]

16 [232]

16 [232]

Charge pump inlet
pressurebar (absolute) [in Hg vacuum]

0.8 [6]

0.8 [6]

Minimum (cold start)

0.2 [24]0.2 [24]

Maximum

2.0

2.0

3 [43]

3 [43]

5 [71]

5 [71]

Case pressure

Minimum (continuous)

Rated

bar [psi]

Maximum
1 No load condition. Refer to System Design Parameters/Charge Pump for details.

MP1 fluid specifications
Features
Viscosity

Temperature range3

Filtration (recommended
minimum)Intermittent1

Units

28/32/38/45

mm2/sec. [ SUS]

5 [42]

Minimum

7 [49]

Recommended range

12 - 80 [66 - 370]

Maximum (cold start)2

1600 [7500]

Minimum (cold start)°C [°F]-40 [-40]

Recommended range

60 - 85 [140 - 185]

Maximum continuous

104 [220]

Maximum intermittent

115 [240]

Cleanliness per ISO 4406

22/18/13

Efficiency (charge pressure filtration)

β-ratio

Efficiency (suction filtration)
Recommended inlet screen mesh size

β15-20=75(β10≥10)β35-45=75(β10≥2)µm

100 - 125

1 Intermittent=Short term t <1 min per incident and not exceeding 2 % of duty cycle based load-life.
2 Cold start = Short term t < 3 min, p < 50 bar [725 psi], n < 1000 min-1 (rpm)3 At the hottest point, normally case drain port.

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Service Manual
MP1
Operation
MP1 high pressure relief valve (HPRV) and charge check
All pumps are equipped with a combination high pressure relief and charge check valve. The highpressure relief function is a dissipative (with heat generation) pressure control valve for the purpose oflimiting excessive system pressures. The charge check function acts to replenish the low-pressure side of
the working loop with charge oil. Each side of the transmission loop has a dedicated HPRV valve that is
non-adjustable with a factory set pressure. When system pressure exceeds the factory setting of thevalve, oil is passed from the high pressure system loop, into the charge gallery, and into the low pressure
system loop via the charge check.
The pump order code allows for different pressure settings to be used at each system port. The systempressure order code for pumps with only HPRV is a reflection of the HPRV setting.
HPRV´s are factory set at a low flow condition. Any application or operating condition which leads toelevated HPRV flow will cause a pressure rise with flow above a valve setting. Consult factory for
application review. Excessive operation of the HPRV will generate heat in the closed loop and may cause
damage to the internal components of the pump.
Low Pressure

High PressureP400353

Bypass function
The bypass function allows a machine or load to be moved without rotating the pump shaft or prime
mover. The single pump HPRV valve also provides a loop bypass function when each of the two HPRV hex
plugs are mechanically backed out three full turns.
Engaging the bypass function mechanically connects both A & B sides of the working loop to thecommon charge gallery.
Possible damage to hydromotor(s).
Excessive speeds and extended load/vehicle movement must be avoided. The load or vehicle should be
moved not more than 20% of maximum speed and for a duration not exceeding 3 minutes. When thebypass function is no longer needed, care should be taken to re-seat the HPRV hex plugs to the normal
operating position.

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Service Manual
MP1
Operation
MP1 charge pressure relief valve (CPRV) function
An internal charge pressure relief valve (CPRV) regulates charge pressure within the hydraulic circuit. The
CPRV is a direct acting poppet valve that regulates charge pressure at a designated level above casepressure.
The charge pressure relief valve setting is specified within the model code of the pump. pumps withcharge pump have the CPRV set at 1800 rpm while MP1 pumps without charge pump have the CPRV set
with 18.9 l/min [5.0 US gal/min] of external supply flow. The charge pressure rise rate, with flow, isapproximately 1 bar/10 liter [5.4 psi/US gal].

Case Drain

Charge PressureP400341

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MP1
Operation
Loop flushing valve
MP1 pumps are available with an optional integral loop flushing. A loop flushing valve will remove heatand contaminants from the main loop at a rate faster than otherwise possible.
The MP1 loop flushing design is a simple spring centered shuttle spool with an orifice plug. The shuttle
shifts at approximately 3.9 bar [55.7 psi]. The flushing flow is a function of the low loop system pressure(charge) and the size of the plug.

Shuttle Spool

Orifice Plug

Working Loop (High Pressure)

Working Loop (Low Pressure)P400342

Loop flushing performance
Oil Temp = 50°C (~30 mm 2/S)

45

Charge pressure [d bar]

40
35
30
25

Ø1.6 (standard)Ø1.9 (optional)

20
15
10
5
0

0

2

4

6

8

Flow [lpm]

10

12

14
P400352

When a pump is used with an external loop flushing shuttle valve, ensure that the charge setting of thepump matches the setting of the loop flushing shuttle valve. Contact your Danfoss representative for theavailability of additional charge relief settings.

© Danfoss | August 2024

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Service Manual
MP1
Operation
Electrical displacement control (EDC)
EDC principle
An EDC is a displacement (flow) control. Pump swashplate position is proportional to the input commandand therefore vehicle or load speed (excluding influence of efficiency), is dependent only on the prime
mover speed or motor displacement.
The Electrical Displacement Control (EDC) consists of a pair of proportional solenoids on each side of athree-position, four-way porting spool. The proportional solenoid applies a force input to the spool,which ports hydraulic pressure to either side of a double acting servo piston. Differential pressure acrossthe servo piston rotates the swashplate, changing the pump‘s displacement from full displacement in
one direction to full displacement in the opposite direction. Under some circumstances, such as
contamination, the control spool could stick and cause the pump to stay at some displacement.
A 170 μm screen is located in the supply line immediately before the control porting spool.
EDC control

P003 191

EDC schematic
M14
C1

C2

F00B

F00A
Feedback from
Swash plate

TP

P003 478E

EDC operation
EDC’s are current driven controls requiring a Pulse Width Modulated (PWM) signal. Pulse widthmodulation allows more precise control of current to the solenoids. The PWM signal causes the solenoid
pin to push against the porting spool, which pressurizes one end of the servo piston, while draining theother. Pressure differential across the servo piston moves the swashplate.
A swashplate feedback link, opposing control links, and a linear spring provide swashplate position force
feedback to the solenoid. The control system reaches equilibrium when the position of the swashplate
spring feedback force exactly balances the input command solenoid force from the operator. As
hydraulic pressures in the operating loop change with load, the control assembly and servo/swashplatesystem work constantly to maintain the commanded position of the swashplate.
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MP1
Operation
The EDC incorporates a positive neutral deadband as a result of the control spool porting, preloads fromthe servo piston assembly, and the linear control spring. Once the neutral threshold current is reached,
the swashplate is positioned directly proportional to the control current. To minimize the effect of thecontrol neutral deadband, we recommend the transmission controller or operator input device
incorporate a jump up current to offset a portion of the neutral deadband.
The neutral position of the control spool does provide a positive preload pressure to each end of theservo piston assembly.
When the control input signal is either lost or removed, or if there is a loss of charge pressure, the springloaded servo piston will automatically return the pump to the neutral position.
Control signal requirements, EDC MP1
Pump displacement vs. control current

Displacement

100 %

-b

-a

"0"

a

Current mA

b

100 %

EDC control current
Voltage

12 VDC

Minimum current to stroke pump

24 VDCa*

640 mA

330 mAb

1640 mA

820 mA

Pin connections

any order* Factory test current, for vehicle movement or application actuation expect higher or lower value.

EDC solenoid data
Description

12 V

24 V

Maximum current

1800 mA

920 mA@ 20 °C [68 °F]

3.66 Ω

14.20 Ω

@ 80 °C [176 °F]

4.52 Ω

17.52 Ω

33 mH

140 mH

Nominal coil resistanceInductance
PWM signal frequency
IP RatingRange

70 – 200 Hz

Recommended*

100 HzIEC 60 529

IP 67

DIN 40 050, part 9

IP 69K with mating connector

Connector colorBlack* PWM signal required for optimum control performance.

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Service Manual
MP1
Operation
Pump output flow direction vs. control signal
Shaft rotation

CW

Coil energized*

CCW

C1

C2

C1

C2

Port A

out

in

in

out

Port B

in

out

out

in

Servo port pressurized

M4

M5

M4

M5

* For coil location see Installation drawings.

Control responsecontrols are available with optional control passage orifices to assist in matching the rate of swash-plate
response to the application requirements (e.g. in the event of electrical failure).
The time required for the pump output flow to change from zero to full flow (acceleration) or full flow tozero (deceleration) is a net function of spool porting, orifices, and charge pressure.
A swash-plate response times table is available for each frame size. Testing should be conducted to verify
the proper orifice selection for the desired response. Typical response times at the following conditions:Δ p = 250 bar [3626 psi]
Charge pressure = 20 bar [290 psi]
Viscosity and temperature = 30 mm²/s [141 SUS] and 50 °C [122 °F]
Speed = 1800 min-1 (rpm)

MP1 EDC response time
Stroking direction

0.8 mm [0.03 in]orifice

1.0 mm [0.04 in]orifice

1.3 mm [0.05 in]orificeNo orifice

28/32

28/32

28/32

28/32

38/45

38/45

38/45

38/45

Neutral to full flow

1.3 s

2.1 s

0.9 s

1.3 s

0.6 s

0.9 s

0.4 s

0.6 s

Full flow to neutral

1.0 s

1.5 s

0.7 s

0.9 s

0.4 s

0.6 s

0.2 s

0.3 s

Manual override (MOR)
Electro-hydraulic controls are available with a Manual Over Ride (MOR) either standard or as an option for
temporary actuation of the control to aid in diagnostics.
Initial actuation of the o-ring seal MOR plunger will require a force of 45 N. Additional actuations typicallyrequire less force to engage the MOR plunger. Proportional control of the pump via the MOR is notintended. The MOR plunger has a 4 mm diameter and must be manually depressed to be engaged.
Depressing the plunger mechanically moves the control spool which allows the pump to go on stroke.
Unintended MOR operation can cause the pump to go into stroke.
The vehicle or device must always be in a safe condition (example: vehicle lifted off the ground) whenusing the MOR function. The MOR should be engaged anticipating a full stroke response from the pump.
Refer to control flow table for the relationship of solenoid to direction of flow.

16 | © Danfoss | August 2024

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Operation
MOR and schematic

M14

C1

C2

F00B
P003 204© Danfoss | August 2024

F00A
Feedback from
Swash plate

TP
P003 205E

AX179786484978en-000405 | 17

Service Manual
MP1
Operation
Hydraulic displacement control (HDC)
HDC principle
An HDC is a Hydraulic Displacement Control. Pump swashplate position is proportional to the input
command and therefore vehicle speed or load speed (excluding influence of efficiency), is dependent
only on the prime mover speed or motor displacement.
The HDC control uses a hydraulic input signal to operate a porting spool, which ports hydraulic pressure
to either side of a double acting servo piston. The hydraulic signal applies a force input to the spool
which ports hydraulic pressure to either side of a double acting servo piston. Differential pressure acrossthe servo piston rotates the swashplate, changing the pump’s displacement from full displacement in
one direction to full displacement in the opposite direction. Under some circumstances, such as
contamination, the porting spool could stick and cause the pump to stay at some displacement.
A serviceable 175 μm screen is located in the supply line immediately before the control porting spool.
HDC control

P400520

HDC schematic
M14

X1

F00B

Feedback from
Swashplate

X2

F00A

T

P
P400519

HDC operation
HDC’s are hydraulically driven control which ports hydraulic pressure to either side of a porting spool,which pressurizes one end of the servo piston, while draining the other end to case. Pressure differential
across the servo piston moves the swashplate.
A swashplate feedback link, opposing control linkage, and a linear spring provide swashplate position
force feedback to the hydraulic pressure. As hydraulic pressures in the operating loop change with load,
the control assembly and servo/swashplate system work constantly to maintain the commanded positionof the swashplate.

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Operation
The HDC incorporates a positive neutral dead band as a result of the control spool porting, preloads fromthe servo piston assembly, and the linear control spring. Once the neutral threshold point is reached, theswashplate is positioned directly proportional to the control pressure.
When the control input is either lost or removed, or if there is a loss of charge pressure, the spring loaded
servo piston will automatically return the pump to the neutral position.
Pump displacement vs signal pressure
Displacement

100 %

-b

-a

"0"

Signal pressure

a

100 %

b

P102 031E

Hydraulic signal pressure range
OptionType

T1Standard

T2

Optiona*b*Max. pressure

4.2 bar16.2 bar

30 bar3 bar

11.6 bar

30 bar* Factory test current, for vehicle movement or application actuation expect a higher or lower value.

Pump output flow direction vs. control pressure
Shaft rotation HDC

Clockwise (CW) seen from shaft

Counter Clockwise (CCW) seen from shaft

Port energized

X1

X2

X1

X2

Port A

Out (high)In (low)

In (low)

Out (high)Port B

In (low)

Out (high)Out (high)In (low)

Servo port highpressure

M4

M5

M4

M5

For appropriate performance of HDC characteristic, keep the drain pressure of pilot valve to be equal orslightly higher than pump case pressure.
Control responsecontrols are available with optional control passage orifices to assist in matching the rate of swash-plate
response to the application requirements (e.g. in the event of electrical failure).
The time required for the pump output flow to change from zero to full flow (acceleration) or full flow tozero (deceleration) is a net function of spool porting, orifices, and charge pressure.
A swash-plate response times table is available for each frame size. Testing should be conducted to verify
the proper orifice selection for the desired response. Typical response times at the following conditions:Δ p = 250 bar [3626 psi]
Charge pressure = 20 bar [290 psi]
Viscosity and temperature = 30 mm²/s [141 SUS] and 50 °C [122 °F]
Speed = 1800 min-1 (rpm)© Danfoss | August 2024

AX179786484978en-000405 | 19

Service Manual
MP1
Operation
Response time, HDC

20 | © Danfoss | August 2024

Stroking
direction

0.8 mm [0.03 in] orifice 1.0 mm [0.04 in] orifice 1.3 mm [0.05 in] orifice No orifice
28/32

38/45

28/32

38/45

28/32

38/45

28/32

38/45

Neutral tofull flow

1.3 s

2.1 s

0.9 s

1.3 s

0.6 s

0.9 s

0.3 s

0.6 s

Full flow to 1.0 s
neutral

1.5 s

0.7 s

0.9 s

0.4 s

0.6 s

0.2 s

0.3 s

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MP1
Operation
Swashplate angle sensor for EDC controls
The angle sensor detects the swash plate position with an accuracy dependent upon the calibration
effort done for the application and direction of rotation from the neutral position. At minimum the sensor
can be used for forward, neutral and reverse (FNR) detection.
The sensor works on the hall-effect technology. The implemented technology is based on ameasurement of the magnetic field direction in parallel to the chip surface. This field direction isconverted to a voltage signal at the output.
Enhanced calibration of the non-linear behavior leads to more exact calculation of the pump swashplateangle. The 4-pin DEUTSCH connector is part of the sensor housing. The swashplate angle sensor isavailable for all EDC controls for 12 V and 24 V.
Swashplate angle vs. output of supply voltage

Sensor output, % of supply voltage

100%
90%
80%
70%
60%
50%
40%
30%
20%
10%
0%
-18°

-13°

-8°

-3°

0°

2°

7°

12°

17°

Swashplate angle

W Warning
Strong magnetic fields in the proximity of the sensor can influence the sensor signal and must be
avoided.
Contact your Danfoss representative in case the angle sensor will be used for safety functions.
Swash plate angle sensor parameters (EDC)© Danfoss | August 2024

Parameter

Minimum

TypicalMaximum

Supply voltage range

4.5 VDC

5 VDC

5.5 VDC

Supply protection––

18 VDC

Pump neutral output (% of supply voltage)

–

50%

–

Working range (swash plate angle)

–18°

–

18°

Required supply current

–

–

30 mA

Output current signal

–

9 mA

11 mA

Working temperature–40 °C

80 °C

115 °CElectrical Protection

StandardClass

IP Rating

IEC 60 529

IP 67

DIN 40 050, part 9

IP 69K with mating connector

EMC Immunity

ISO 11452-2

100 V/m

AX179786484978en-000405 | 21

Service Manual
MP1
Operation
Calibration of the sensor output within the software is mandatory. Vehicle neutral thresholds in thesoftware (±0.5°) are vehicle dependent and must consider different conditions, example: systemtemperature, system pressure and/or shaft speed.
For safety function: If the sensor fails (invalid signal <10% or >90% of supply voltage), it must be surethat the ECU will go into a diagnostic mode and shift into limited mode in order for the driver to take thefull control or the mechanical breaks should be activated. Strong magnetic fields in the proximity of thesensor can influence the sensor signal and must be avoided.
Swash plate angle sensor connector
Connector DEUTSCH, 4-pin

Pin assignment:

4

1

1. Ground (GND)
2. Not connected
3. Output signal 1 (SIG 1)
4. Supply (V+)

32

Connector order numbers
Description

Quantity

Order number

Mating connector DEUTSCH DTM06-4S-E004

111105824

Wedge lock WM-4S

1

Socket contact 0462-201-2031

3

Mating connector kit

1

not available
11212713

Interface with ECU (EDC)
Interface with ECU diagram

Supply100 nF
VCC

ECU

SignalOUT
100 nF

20 kΩ

GND

GND

Manual displacement control (MDC)
MDC principle
An MDC is a Manual proportional Displacement Control (MDC). The MDC consists of a handle on top of arotary input shaft. The shaft provides an eccentric connection to a feedback link. This link is connected on
its one end with a porting spool. On its other end the link is connected the pumps swashplate.
This design provides a travel feedback without spring. When turning the shaft the spool moves thus
providing hydraulic pressure to either side of a double acting servo piston of the pump.
Differential pressure across the servo piston rotates the swash plate, changing the pump’s displacement.
Simultaneously the swashplate movement is fed back to the control spool providing proportionality
between shaft rotation on the control and swashplate rotation.
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Operation
The MDC changes the pump displacement between no flow and full flow into opposite directions. Under
some circumstances, such as contamination, the control spool could stick and cause the pump to stay atsome displacement.
A 170 μm screen is located in the supply line immediately before the control porting spool.
The MDC is sealed by means of a static O-ring between the actuation system and the control block. Its
shaft is sealed by means of a special O-ring which is applied for low friction. The special O-ring is
protected from dust, water and aggressive liquids or gases by means of a special lip seal.
Manual Displacement Control

P301 749

Pump displacement vs. control lever rotation

Displacement

100 %

"A"

-d -b

-a

-c

"0"

d

Lever rotation
a

100 %

bc

"B"

P301 752

MDC schematic diagram
M14

M5

M4

M3
P005 701

Where:
Deadband on B side – a = 3° ±1°
Maximum pump stroke – b = 30° +2/-1°© Danfoss | August 2024

AX179786484978en-000405 | 23

Service Manual
MP1
Operation
Required customer end stop – c = 36° ±3°Internal end stop – d = 40°
MDC torque
Torque required to move handle to maximum displacement

1.4 N•m [12.39 lbf•in ]Torque required to hold handle at given displacement

0.6 N•m [5.31 lbf•in]Maximum allowable input torque

20 N•m [177 lbf•in]

MDC operation
The MDC provides a mechanical dead-band required to overcome the tolerances in the mechanicalactuation. The MDC contains an internal end stop to prevent turning the handle into any inappropriate
position.
The MDC provides a permanent restoring moment appropriate for turning the MDC input shaft back toneutral position only. This is required to take the backlash out of the mechanical connections between
the Bowden cable and the control.
High case pressure may cause excessive wear and the NSS to indicate that the control is not in neutral
position. In addition, if the case pressure exceeds 5 bar there is a risk of an insufficient restoring moment.
The MDC is designed for a maximum case pressure of 5 bar and a rated case pressure of 3 bar.

•••

Customers must install some support to limit the setting range of their Bowden cable to avoid anoverload of the MDC.
Customers can apply their own handle design but they must care about a robust clamping
connection between their handle and the control shaft and avoid overload of the shaft.
Customers can connect two MDC’s on a tandem unit in such a way that the actuation force will betransferred from the pilot control to the second control. The kinematic of the linkages must ensurethat either control shaft is protected from torque overload.

C Caution
Using the internal spring force on the input shaft is not an appropriate way to return the customer
connection linkage to neutral, or to force a Bowden cable or a joystick back to neutral position. It is notapplicable for any limitation of the Bowden cable stroke, except the applied torque to the shaft will neverexceed 20 N•m.
MDC shaft rotation

CCW

CW

Pump shaft rotation*

Clockwise (CW)MDC shaft rotation

CW

CCW

Port Ain (low)out (high)out (high)in (low)

Port Bout (high)in (low)in (low)out (high)Servo port high pressure

M5

M4

M5

M4

Counter-clockwise (CCW)CW

CCW* As seen from shaft side.

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MP1
Operation
Control responsecontrols are available with optional control passage orifices to assist in matching the rate of swash-plate
response to the application requirements (e.g. in the event of electrical failure).
The time required for the pump output flow to change from zero to full flow (acceleration) or full flow tozero (deceleration) is a net function of spool porting, orifices, and charge pressure.
A swash-plate response times table is available for each frame size. Testing should be conducted to verify
the proper orifice selection for the desired response. Typical response times at the following conditions:Δ p = 250 bar [3626 psi]
Charge pressure = 20 bar [290 psi]
Viscosity and temperature = 30 mm²/s [141 SUS] and 50 °C [122 °F]
Speed = 1800 min-1 (rpm)MP1 MDC response time
Code

Orifice description (mm)P

A

Stroking direction (sec)
B

Tank (A+B)

Neutral to full flow

Full flow to neutral

28/32

38/45

28/32

38/45

C1

–

0.8

0.8

–

1.3

1.8

0.9

1.2

C2

–

1.3

1.3

–

0.5

0.7

0.4

0.5

C3

–

–

–

–

0.3

0.3

0.3

0.3

C4

–

1.0

1.0

–

0.8

1.1

0.6

0.8

C6

–

–

–

1.0

0.5

1.0

0.5

0.7

C7

–

–

–

1.3

0.4

0.7

0.5

0.5

C8

0.8

–

–

0.6

1.5

2.6

1.4

1.9

C9

1.0

–

–

0.6

1.3

2.4

1.1

1.8

D1

1.0

–

–

0.8

0.9

1.6

0.8

1.1

D2

1.3

–

–

0.8

0.8

1.5

0.7

1.1

D3

1.3

–

–

1.0

0.6

1.1

0.6

0.8

D4

1.3

1.3

1.3

1.0

0.8

1.3

0.7

0.9

D5

0.6

0.8

0.8

0.6

3.2

4.0

2.0

2.9

E2

1.0

0.8

0.8

0.8

2.1

2.9

1.2

1.7

Neutral start switch (NSS)The Neutral Start Switch (NSS) contains an electrical switch that provides a signal of whether the control
is in neutral. The signal in neutral is Normally Closed (NC).

© Danfoss | August 2024

AX179786484978en-000405 | 25

Service Manual
MP1
Operation
Neutral start switch schematic
M14

M5

M4

M3
P005 702

Neutral start switch data
Max. continuous current with switching

8.4 A

Max. continuous current without switching

20 A

Max. voltage

36 VDCElectrical protection class

IP67 / IP69K with mating connector

Case gauge port M14
The drain port should be used when the control is mounted on the unit’s bottom side to flush residual
contamination out of the control.
MDC w/h drain port shown
Case gauge port M14

P400344

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Operation
MDC schematic diagram
M14

M5

M4

M3
P005 701

Lever
MDC controls are available with optional lever/handle. Align with Settings: Y module in the model code.
Standard orientation 90° from input shaft

P301 749

Forward-neutral-reverse electic control (FNR)
FNR principle
The 3-position FNR control uses an electric input signal to switch the pump to a full stroke position.
Under some circumstances, such as contamination, the control spool could stick and cause the pump tostay at some displacement.
A 170 μm screen is located in the supply line immediately before the control porting spool.

© Danfoss | August 2024

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Service Manual
MP1
Operation
Forward-Neutral-Reverse electric control (FNR)

P003 193

FNR hydraulic schematic
M14
C1

C2

F00B

F00A

T

P
P003 189

Pump displacement vs. electrical signal

Displacement

100 %

“0“

Voltage VDC

100 %P003 190E

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Operation
Control current
Voltage

Min. current to stroke pump

Pin connections

12 V

750 mAany order

24 V

380 mADEUTSCH connector, 2-pin

12P003 480

Connector ordering data
Description

Quantity

Ordering data

Mating connector

1

DEUTSCH DT06-2S

Wedge lock1

DEUTSCH W2S

Socket contact (16 and 18 AWG)

2

DEUTSCH 0462-201-16141

Danfoss mating connector kit

1

K29657

Solenoid data
Voltage

12 V

24 V

Minimum supply voltage

9.5 VDC

19 VDC

Maximum supply voltage (continuous)

14.6 VDC

29 VDC

Maximum current

1050 mA

500 mA

Nominal coil resistance @ 20 °C [70 °F]

8.4 Ω

34.5 Ω

PWM Range

70-200 Hz

PWM Frequency (preferred)*

100 HzIP Rating (IEC 60 529) + DIN 40 050, part 9

IP 67 / IP 69K (part 9 with mating connector)

Bi-directional diode cut off voltage

28 VDC

53 VDC* PWM signal required for optimum control performance.

Pump output flow direction vs. control signal
Shaft rotation

CW

Coil energized*

CCW

C1

C2

C1

C2

Port A

in

out

out

in

Port B

out

in

in

out

Servo port pressurized

M5

M4

M5

M4

* For coil location see Installation Drawings.

Control responsecontrols are available with optional control passage orifices to assist in matching the rate of swash-plate
response to the application requirements (e.g. in the event of electrical failure).
The time required for the pump output flow to change from zero to full flow (acceleration) or full flow tozero (deceleration) is a net function of spool porting, orifices, and charge pressure.
© Danfoss | August 2024

AX179786484978en-000405 | 29

Service Manual
MP1
Operation
A swash-plate response times table is available for each frame size. Testing should be conducted to verify
the proper orifice selection for the desired response. Typical response times at the following conditions:Δ p = 250 bar [3626 psi]
Charge pressure = 20 bar [290 psi]
Viscosity and temperature = 30 mm²/s [141 SUS] and 50 °C [122 °F]
Speed = 1800 min-1 (rpm)Response time, FNR
Stroking
direction

0.8 mm [0.03 in] orifice 1.0 mm [0.04 in] orifice 1.3 mm [0.05 in] orifice No orifice
28/32

38/45

28/32

38/45

28/32

38/45

28/32

38/45

Neutral tofull flow

2.1 s

2.6 s

1.1 s

1.6 s

0.8 s

1.1 s

0.7 s

0.7 s

Full flow to 1.1 s
neutral

1.8 s

0.9 s

1.0 s

0.6 s

0.7 s

0.3 s

0.3 s

Non feedback proportional electric control (NFPE)The Non Feedback Proportional Electric (NFPE) control is an electrical automotive control in which an
electrical input signal activates one of two proportional solenoids that port charge pressure to either sideof the pump servo cylinder. The NFPE control has no mechanical feedback mechanism.
A serviceable 170 μm screen is located in the supply line immediately before the control porting spool.
Under some circumstances, such as contamination, the control spool could stick and cause the pump tostay at some displacement.
NFPE control

NFPE schematic
M14
C1

C2

F00B

F00A

T

P
P003 188

P003 192

The pump displacement is proportional to the solenoid signal current, but it also depends upon pump
input speed and system pressure. This characteristic also provides a power limiting function by reducing
the pump swashplate angle as system pressure increases. A typical response characteristic is shown in
the accompanying graph. Under some circumstances, such as contamination, the control spool could
stick and cause the pump to stay at some displacement.

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Operation
NFPE pump displacement to input signal
100 %

c

′p

Signal Current
mA(DC)

′p

=0

bar

= 30
0 ba

r

NFPE control

a

b

a

b

c

Displacement

bar
=0
′p

′p

= 30
0 ba

r

"0"

P003 187E

100 %Control signal requirements
Control current
Voltagea*bc

Pin connections

12 V

600 mA

1080 mA

1360 mA

any order

24 V

300 mA

540 mA

680 mA* Factory test current, for vehicle movement or application actuation expect higher or lower value.

DEUTSCH connector, 2-pin

12P003 480

Connector ordering data
Description

Quantity

Ordering data

Mating connector

1

DEUTSCH DT06-2S

Wedge lock1

DEUTSCH W2S

Socket contact (16 and 18 AWG)

2

DEUTSCH 0462-201-16141

Danfoss mating connector kit

1

K29657

Description

12 V

24 V

Maximum current

1800 mA

920 mA@ 20 °C [68 °F]

3.66 Ω

14.20 Ω

@ 80 °C [176 °F]

4.52 Ω

17.52 Ω

33 mH

140 mH

Nominal coil resistanceInductance
PWM signal frequency
IP RatingRange

70 – 200 Hz

Recommended*

100 HzIEC 60 529

IP 67

DIN 40 050, part 9
Connector color

IP 69K with mating connectorBlack* PWM signal required for optimum control performance.

© Danfoss | August 2024

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Service Manual
MP1
Operation
Pump output flow direction vs. control signal
Shaft rotation

CW

Coil energized*

CCW

C1

C2

C1

C2

Port A

in

out

out

in

Port B

out

in

in

out

Servo port pressurized

M5

M4

M5

M4

* For coil location see Installation drawings.

Control response
MP1 controls are available with optional control passage orifices to assist in matching the rate ofswashplate response to the application requirements (e.g. in the event of electrical failure). The timerequired for the pump output flow to change from zero to full flow (acceleration) or full flow to zero(deceleration) is a net function of spool porting, orifices, and charge pressure. A swashplate response
table is available for each frame indicating available swashplate response times. Testing should be
conducted to verify the proper orifice selection for the desired response.
Typical response times at the following conditions:∆p

250 bar [3626 psi]

Viscosity and temperature

30 mm2/s [141 SUS] and 50°C [122 °F]

Charge pressure

24 bar [348 psi]

Speed

1800 min-1 (rpm)Response time
Stroking
direction

0.8 mm [0.03] orifice

1.0 mm [0.04] orifice

1.3 mm [0.05] orifice

28/32

38/45

28/45

38/45

28/45

38/45

Neutral to full
flow

1.5 s

2.2 s

0.9 s

1.4 s

0.6 s

0.8 s

Full flow toneutral

0.9 s

1.1 s

0.6 s

0.7 s

0.4 s

0.5 s

Non-feedback, proportional hydraulic control (NFPH)
The non-feedback proportional hydraulic (NFPH) control is a hydraulic proportional control in which an
input pressure signal directly controls the pump servo piston to achieve pump displacement.
pumps with NFPH control have a special servo cylinder capable of providing proportional control with ahydraulic input.
Swashplate position is proportional to the differential signal pressure at ports X1 and X2, butdisplacement is also dependent on pump speed and system pressure. This characteristic of non-feedback
controls provides a natural power limiting function by reducing the pump swashplate angle as systempressure increases. The accompanying graph shows typical operating characteristics.
The system may require tuning through the pump orifice combinations, control pressure supply line
sizing, actuation device output pressure and flow adjustments to achieve proper vehicle performance
characteristics.

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Operation
Non-feedback proportional hydraulic control schematic
X1 X2

L2

M5

M4

Pump flow direction with NFPH control
Input Shaft Rotation

CW

CCW

Port A flow

Out

In

In

Out

Port B flow

In

Out

Out

In

High servo gauge port

M4

M5

M4

M5

NFPH pump displacement to Input signal
100 %

c

′p

Signal Current
mA(DC)

′p

=0

= 30

bar

0 ba

r

NFPE control

a

b

a

b

c

Displacement

bar
=0
′p

′p

= 30

0 ba

r

"0"

100 %

P003 187E

NFPH input signal pressure (bar)Frame size

a

b

c

28/32

5.5

13.7

17

38/45

5

12.75

16

The values provided in the table above are approximations at 1800 RPM and system delta pressures as
indicated in the graph provided. The values are dependent on input speed and delta pressure operating
conditions.
Control response
MP1 controls are available with optional control passage orifices to assist in matching the rate ofswashplate response to the application requirements (e.g. in the event of electrical failure). The timerequired for the pump output flow to change from zero to full flow (acceleration) or full flow to zero(deceleration) is a net function of spool porting, orifices, and charge pressure. A swashplate response© Danfoss | August 2024

AX179786484978en-000405 | 33

Service Manual
MP1
Operation
table is available for each frame indicating available swashplate response times. Testing should be
conducted to verify the proper orifice selection for the desired response.
Typical response times at the following conditions:∆p

250 bar [3626 psi]

Viscosity and temperature

30 mm2/s [141 SUS] and 50°C [122 °F]

Charge pressure

24 bar [348 psi]

Speed

1800 min-1 (rpm)Response time
Stroking
direction

0.8 mm [0.03] orifice

1.0 mm [0.04] orifice

1.3 mm [0.05] orifice

28/32

38/45

28/45

38/45

28/45

38/45

Neutral to full
flow

1.5 s

2.2 s

0.9 s

1.4 s

0.6 s

0.8 s

Full flow toneutral

0.9 s

1.1 s

0.6 s

0.7 s

0.4 s

0.5 s

Automotive control (AC)The Automotive control (AC) is an electric NFPE control with an integrated micro-controller, installed on
the pump.
The integrated micro-controller enhanced control performance with a flexible, configurable control
scheme for an entire single path propel transmission. It can be used in combination with fixed andvariable displacement hydraulic motors. With the pre-installed application software and easilychangeable control parameters, it is possible to tailor the vehicle’s driving behavior to the individual
requirements of the customer.

CC1
WARRANTY VOID IF REMOVEDCAN PPC PSC PPU

CC3

CC2
P003 544

The H1 automotive control is divided into 2 systems:
AC-1
AC-2

•
•

AC-2 is an extension of AC-1 that features an integrated pump swash plate angle sensor and software
enabled functions such as swash plate control.

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MP1
Operation
Mode types
The application software provides 3 different hydrostatic propel methods, defined as mode types, which
can be used individually.
Automotive Loaddependent

Torque controlled driving behavior. Setpoint for the drive curve is the enginerpm.

Non-Automotive
Load independent

Speed controlled driving mode. Setpoint for the drive curve is a joystick ordrive pedal signal, independent of the engine rpm. The best performance willachieved with an AC-2 Swash Plate Sensor.

Creep-Automotive
Load dependent

Torque controlled driving behavior (like Automotive). Setpoint for the drive
curve is the engine rpm. The setpoint can be reduced by the creep
potentiometer if a high engine rpm in combination with low vehicle speed isneeded.

Basic functions

•
•
•
•
•
•
•
•
•

Four selectable system modes, selectable via switch
Individual settings for forward and reverse driving direction (4 x 2 curves)
Independent pump and hydraulic motor profiling and ramping for each mode
Electric drive pedal connection
Electronic inching function without separate control valve
Electric creep mode potentiometer
Configurable System Mode and Direction change
Load independent pump displacement control with integrated Swash Plate Angle Sensor (AC-2)
Hydraulic motor displacement control including brake pressure defeat function

Performance functions

•
•
•
•
•
•
•

ECO fuel saving mode with automatic reduction of the engine speed during transport (Cruise control)
Vehicle constant speed drive control
Vehicle speed limitation
Dynamic brake light, automatic park brake, reverse buzzer and status LED outputs
Vehicle speed controlled output function
Temperature compensation for predictable performance
Advanced CAN J1939 interface for the information exchange with the vehicle control system

Protection and safety functions

•
•
•
•
•
•

© Danfoss | August 2024

Safety controlled vehicle start protection with engine speed check, battery check and FNR must be inneutral, etc.
Operator presence detection
Hydraulic system overheat and low-temperature protection
Hydraulic motor over speed protection
Park brake test mode for roller applications to fulfill SAE J1472/EN500-4
SIL2 compliant

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Service Manual
MP1
Operation
Engine control and protection

•
•
•
•
•
•

CAN J1939 engine interface
Engine speed control via drive pedal with safety controlled monitoring function
Engine antistall protection
Engine over speed protection during inching
Engine speed dependent retarder control
Engine cold start protection

Installation features•••

Factory calibration for hysteresis compensation
Starting current adjustment in the factory
Pre-installed application software and parameter files

For more information, see Integrated Automotive Control (AC) for MP1 and H1P Single Pumps 28-250
Technical Information, BC152986482596.

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Operation
Control-cut-off valve (CCO valve)
The pump offers an optional control cut off valve integrated into the control. This valve will block chargepressure to the control, allowing the servo springs to de-stroke the pump regardless of the pump´sprimary control input. There is also a hydraulic logic port, X7, which can be used to control other machinefunctions, such as spring applied pressure release brakes. The pressure at X7 is controlled by the control
cut off solenoid. The X7 port would remain plugged if not needed.
In the normal (de-energized) state of the solenoid charge flow is prevented from reaching the controls. At
the same time the control passages and the X7 logic port are connected and drained to the pump case.
The pump will remain in neutral, or return to neutral, independent of the control input signal. Return toneutral time will be dependent on oil viscosity, pump speed, swashplate angle, and system pressure.
When the solenoid is energized, charge flow and pressure is allowed to reach the pump control. The X7
logic port will also be connected to charge pressure and flow.
The solenoid control is intended to be independent of the primary pump control making the control cut
off an override control feature. It is however recommended that the control logic of the CCO valve bemaintained such that the primary pump control signal is also disabled whenever the CCO valve is deenergized. Other control logic conditions may also be considered.
All EDC and MDC controls are available with a CCO valve.
The response time of the unit depends on the control type and the control orifices used.
The CCO-valve is available with 12 V or 24 V solenoid.
EDC with CCO
ControlHydraulic logic Port X7

P400346

Schematic
M14

C1

X7

C2

P400349© Danfoss | August 2024

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Service Manual
MP1
X7

Operation
MDC with CCO
Control

Schematic
M14

X7

P005 703

1

2

CCO solenoid data
Nominal supply voltage
Supply voltage

24 V

Maximum

14.6 V

29 V

Minimum

9.5 V

19 V

Bi-directional diode cut off voltage

28 V

53 V

Nominal coil resistance at 20 °C

10.7 Ω

41.7 ΩMaximum

850 mA430 mA

Minimum

580 mA

300 mARange

50 – 200 Hz

Preferred

100 HzSupply current

PWM frequency

Electrical protection class38 | © Danfoss | August 2024

12 V

IP67 / IP69K with mating connector

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Operation
CCO solenoids are design for battery voltage application within the voltage range in the table above, inconsideration of a wide range of environmental temperature common for known hydraulic applications.
Closed loop PWM current supply can be also applied and is helpful in case that the voltage range is
exceeded, or ambient temperature could rise in an unusual manner.
Brake gauge port with MDC

C Caution
It is not recommended to use brake port for any external flow consumption to avoid malfunction of CCO
function.

Displacement limiter
All pumps are designed with optional mechanical displacement (stroke) limiters factory set to max.
displacement.
The maximum displacement of the pump can be set independently for forward and reverse using thetwo adjustment screws to mechanically limit the travel of the servo piston. Adjustment procedures arefound in the Service Manual. Adjustments under operating conditions may cause leakage. The
adjustment screw can be completely removed from the threaded bore if backed out to far.
Displacement limiter
Servo piston

Displacement limiter

Servo cylinder

P400347

Displacement change (approximate)© Danfoss | August 2024

Parameter

28

32

38

45

1 Turn ofdisplacement limiter screw

2.9 cm3[0.18 in3]

3.3 cm3

3.56 cm3

4.22 cm3[0.26 in3]

Internal wrench size

4 mmExternal wrench size

13 mm

Torque forexternal hex seal lock nut

23 N•m [204 lbf•in][0.20 in3]

[0.22 in3]

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MP1
Operation
Speed sensor
The speed sensor is designed for rugged outdoor, mobile or heavy industrial speed sensing applications.
The detection of the speed is contactless and does not need any calibration or adjustments.
For more information, see Speed and Temperature Sensor, Technical Information, BC152886482203.
Temperature Range
Parameter

Minimum

Maximum

Operation temperature range-40 °C

104 °C

115°C intermittent = short term; t < 1min per incident and not exceeding 2 % of duty cycle based loadlife.
Output pulses
The expected number of output pulses per revolution is shown below.
The number of output (speed) pulses
MP1P size

28/32

38/45

Pulses (per rev)

9

11

Mating connectors
There are available two types of mating connectors Assembly Bag DEUTSCH DTM06-6S, Black and Grey.
Ordering number
11033865

11033863

Assembly Bag, DEUTSCH DTM06-6S-E004; black, (24-20
AWG) 0.21 -0.52 mm²Assembly Bag, DEUTSCH DTM06-6S, gray, (24-20 AWG)
0.21 -0.52 mm²

Speed sensor 4.5 – 8 V
1. Speed signal 2
2. NC
3. Speed signal 1
4. Supply
5. Ground
6. Temperature

Speed sensor connector, 6-pin
4 56
3 2 1
P006035

Technical data

40 | © Danfoss | August 2024

Parameter

Min.

Nom.

Max.

Note

Supply voltage

4.5 VDC

5 VDC

8 VDC

Regulated supply voltage.
Reverse polarity protected.

Supply protection––

30 VDC

Shuts off above 9 V.

Max. required supply current

–

–

25 mA

At supply voltage

Max. output current

–

–

50 mA

Operation mode

NPN & PNP

Temperature signal-40°C = 2.318V–

100°C = 0.675V

Output low

5%

8.5 %

12 %

Push-Pull amplifier

Ratiometric output voltage
Low state > 0 V to provide wire
fault detection

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MP1
Operation
Technical data (continued)
Parameter

Min.

Nom.

Max.

Note

Output high88 %91.5 %

95 %Detectable frequency range

1 Hz

–

10 000 Hz

Ordering number

149055

Color of connector

Black

Temperature Signal
For calculation of the case fluid temperature and the output signal voltage, see the formulas below:
VO – Measured output voltage (V)Vo= (-3.88 • 10-6 • T2) + (-1.15 • 10-2 • T) + 1.8639
T – Temperature (°C)
T = –1481.96 + √ 2.1962 · 10 6 +(1.8639 – Vº)
3.88 · 10 -6

Output signal voltage vs. Temperature
Temperature range-55 °C**-40 °C-30 °C

0 °C+30 °C*+80 °C+100 °C+130 °C**

2.485 V2.318 V

2.205 V1.864 V1.515 V

0.919 V

0.675 V

0.303 V

* Accuracy: ±1. 5 to ± 4 °C** Accuracy: ±2.5 to ± 5 °C

Response time in fluid
T90 definition
T90 definition
90

60
50

90 % of ′ Temp

70
′ TempTemperature (°C)

8040Real temperature
Temperature
Signal

30
20
10
0
-100

T90

0

100

200

300

400
500
Time (S)

600

700

800

900

1000
P003531E

Response time in fluid (T90) = 360 s© Danfoss | August 2024

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Service Manual
MP1
Operating parameters
Input speed
Minimum speed is the lowest input speed recommended during engine idle condition. Operating below
minimum speed limits pump’s ability to maintain adequate flow for lubrication and power transmission.
Rated speed is the highest input speed recommended at full power condition. Operating at or below
this speed should yield satisfactory product life.
Maximum speed is the highest operating speed permitted. Exceeding maximum speed reduces productlife and can cause loss of hydrostatic power and braking capacity. Never exceed the maximum speed
limit under any operating conditions.
Operating conditions between Rated speed and Maximum speed should be restricted to less than fullpower and to limited periods of time. For most drive systems, maximum unit speed occurs during
downhill braking or negative power conditions.
During hydraulic braking and downhill conditions, the prime mover must be capable of providing
sufficient braking torque in order to avoid pump over speed. This is especially important to consider forturbocharged and Tier 4 engines.

W Warning
Unintended vehicle or machine movement hazard.
Exceeding maximum speed may cause a loss of hydrostatic drive line power and braking capacity. You
must provide a braking system, redundant to the hydrostatic transmission, sufficient to stop and hold thevehicle or machine in the event of hydrostatic drive power loss.

System Pressure
System pressure is the differential pressure between system ports A and B. It is the dominant operating
variable affecting hydraulic unit life. High system pressure, which results from high load, reduces
expected life. Hydraulic unit life depends on the speed and normal operating, or weighted average,pressure that can only be determined from a duty cycle analysis.
Application pressure is the high pressure relief setting normally defined within the order code of thepump. This is the applied system pressure at which the driveline generates the maximum calculated pullor torque in the application.
Maximum working pressure is the highest recommended Application pressure. Maximum working
pressure is not intended to be a continuous pressure. Propel systems with Application pressures at, or
below, this pressure should yield satisfactory unit life given proper component sizing.
Maximum pressure is the highest allowable Application pressure under any circumstance. Applicationpressures above Maximum Working Pressure will only be considered with duty cycle analysis and factory
approval. Pressure spikes are normal and must be considered when reviewing maximum working
pressure.
All pressure limits are differential pressures referenced to low loop (charge) pressure. Subtract low looppressure from gauge readings to compute the differential.
Minimum low loop pressure (above case pressure) is the lowest pressure allowed to maintain a safe
working condition in the low side of the loop.

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Operating parameters
Charge pressure
An internal charge relief valve regulates charge pressure. Charge pressure maintains a minimum pressurein the low side of the transmission loop.
The charge pressure setting listed in the order code is the set pressure of the charge relief valve with thepump in neutral, operating at 1800 min-1 [rpm], and with a fluid viscosity of 32 mm2/s [150 SUS]. Pumps
configured with no charge pump (external charge supply) are set with a charge flow of 18.9 l/min [5.0 US
gal/min] and a fluid viscosity of 32 mm2/s [150 SUS].
The charge pressure setting is referenced to case pressure.
Charge pump inlet pressure
At normal operating temperature charge inlet pressure must not fall below rated charge inlet pressure(vacuum).
Minimum charge inlet pressure is only allowed at cold start conditions. In some applications it isrecommended to warm up the fluid (e.g. in the tank) before starting the engine and then run the engine
at limited speed until the fluid warms up.
Maximum charge pump inlet pressure may be applied continuously.
Case pressure
Under normal operating conditions, the rated case pressure must not be exceeded. During cold start casepressure must be kept below maximum intermittent case pressure. Size drain plumbing accordingly.

C Caution
Possible component damage or leakage
Operation with case pressure in excess of stated limits may damage seals, gaskets, and/or housings,
causing external leakage. Performance may also be affected since charge and system pressure are
additive to case pressure.

Temperature
The high temperature limits apply at the hottest point in the transmission, which is normally the motor
case drain. The system should generally be run at or below the rated temperature.
The maximum intermittent temperature is based on material properties and should never be
exceeded.
Cold oil will not affect the durability of the transmission components, but it may affect the ability of oil toflow and transmit power; therefore temperatures should remain 16 °C [30 °F] above the pour point of thehydraulic fluid.
The minimum temperature relates to the physical properties of component materials. Size heatexchangers to keep the fluid within these limits. Danfoss recommends testing to verify that thesetemperature limits are not exceeded.
Ensure fluid temperature and viscosity limits are concurrently satisfied.

© Danfoss | August 2024

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MP1
Operating parameters
Viscosity
Viscosity For maximum efficiency and bearing life, ensure the fluid viscosity remains in therecommended range.
The minimum viscosity should be encountered only during brief occasions of maximum ambient
temperature and severe duty cycle operation.
The maximum viscosity should be encountered only at cold start.

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Fluid and filter maintenanceFiltration system
To prevent premature wear, ensure that only clean fluid enters the hydrostatic transmission circuit. A
filter capable of controlling the fluid cleanliness to ISO 4406, class 22/18/13 (SAE J1165) or better, undernormal operating conditions, is recommended.These cleanliness levels cannot be applied for hydraulicfluid residing in the component housing/case or any other cavity after transport.
Filtration strategies include suction or pressure filtration. The selection of a filter depends on a number offactors including the contaminant ingression rate, the generation of contaminants in the system, therequired fluid cleanliness, and the desired maintenance interval. Filters are selected to meet the above
requirements using rating parameters of efficiency and capacity.
Filter efficiency can be measured with a Beta ratio (βX). For simple suction-filtered closed circuit
transmissions and open circuit transmissions with return line filtration, a filter with a β-ratio within therange of β35-45 = 75 (β10 ≥ 2) or better has been found to be satisfactory. For some open circuit systems,
and closed circuits with cylinders being supplied from the same reservoir, a higher filter efficiency isrecommended. This also applies to systems with gears or clutches using a common reservoir. For thesesystems, a charge pressure or return filtration system with a filter β-ratio in the range of β15-20 = 75 (β10 ≥10) or better is typically required.
Because each system is unique, only a thorough testing and evaluation program can fully validate thefiltration system. Please see Design Guidelines for Hydraulic Fluid Cleanliness Technical Information,
BC152886482150 for more information.
Cleanliness level and βx-ratio1
Filtration(recommended
minimum)

Cleanliness per ISO 4406
Efficiency (charge pressure
filtration)
Efficiency (suction and return line
filtration)
Recommended inlet screen meshsize

22/18/13
β15-20 = 75 (β10 ≥ 10)
β-ratio
β35-45 = 75 (β10 ≥ 2)µm

100 – 125

1 Filter β -ratio is a measure of filter efficiency defined by ISO 4572. It is defined as the ratio of the number of particles
x

greater than a given diameter (“x” in microns) upstream of the filter to the number of these particles downstream of
the filter.

© Danfoss | August 2024

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Service Manual
MP1
Pressures measurements
MP1 port locations and gauge installation
The following table and drawing show the port locations and gauge sizes needed. When testing systempressures, calibrate pressure gauges frequently to ensure accuracy. Use snubbers to protect gauges.
Port description
Port

Pressure obtained

Gauge size

Inch/metricSize port

Wrench size

AM3

Charge pressure

50 bar [1000 psi]

Inch

9/16-18

1/4 inch

MetricM14x1.5

6 mm

9/16-18

1/4 inch

E/F

Filtration inlet/outlet-

Inch
MetricM14x1.5

6 mm

L1/L2

Case pressure

10 bar [100 psi]

Inch

1 1/16-12

9/16 inch

Metric

M27x2

12 mm

Inch

9/16-18

11/16 inch

MetricM14x1.5

19 mm

Inch

3/4-16

7/8 inch

MetricM18x1.5

24 mm

9/16-18

1/4 inch

MA/MB (28/32)
MA/MB (38/45)

System A, B pressure
System A, B pressure

600 bar [10,000 psi]
600 bar [10,000 psi]

M3

Charge pressure

50 bar [1000 psi]

Inch
MetricM14x1.5

6 mm

M4/M5 (28/32)

Servo pressure

50 bar [1000 psi]

Inch

7/16-20

3/16 inch

MetricM12x1.5

6 mm

Inch

9/16-18

1/4 inch

MetricM14x1.5

6 mm

Inch

7/16-20

1/4 inch

MetricM12x1.5

6 mm

1 1/16-12

9/16 inch

M4/M5 (38/45)
M14

Servo pressure
Case pressure

50 bar [1000 psi]
10 bar [100 psi]

S

Charge pump Inlet-

Inch
Metric

M27x2

12 mm

X1, X2

Hydraulic control input

-

Inch

9/16-18

1/4 inch

MetricM14x1.5

6 mm

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Pressures measurements
Port locations
M14

F

28/32
X1

X2

AM3
E
L2

M5

M3

AM3

M4

MB

S MA

A

B

L1

38/45
M14

F

X1

X2

B

A
AM3
E
M5

L2

AM3

M4
M3
B

MB

© Danfoss | August 2024

MA

S

A

L1

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Service Manual
MP1
Initial startup procedure
GeneralFollow this procedure when starting-up a new pump installation or when restarting an installation inwhich the pump has been removed and re-installed on a machine. Ensure pump has been thoroughly
tested on a test stand before installing on a machine.

W Warning
Unintended movement of the machine or mechanism may cause injury to the technician or bystanders.
To protect against unintended movement, secure the machine or disable/disconnect the mechanism
while servicing.
Prior to installing the pump, inspect for damage that may have occurred during shipping.
MP1 start-up procedure
Follow this procedure when starting-up a new pump installation or when restarting an installation inwhich the pump has been removed and re-installed on a machine.
Prior to installing the pump on a machine, inspect for damage and ensure pump has been thoroughly
tested on a test stand before installing on a machine.
Unintended movement of the machine or mechanism may cause injury to the technician or bystanders.
Ensure the machine is secured or disable/disconnect the mechanism while servicing.
1. Ensure that the machine hydraulic oil and system components (reservoir, hoses, valves, fittings, andheat exchanger) are clean and free of any foreign material.
2. Install new system filter element(s) if necessary. Check that inlet line fittings are properly tightened
and there are no air leaks.
3. Install the pump. Install a 50 bar [1000 psi] gauge in the charge pressure gauge port M3.
4. Fill the housing by adding filtered oil in the upper case drain port. If the control is installed on top,
open M14 plug in the top of the control to assist in air bleed.
5. Fill the reservoir with hydraulic fluid of the recommended type and viscosity. Use a 10-micron filler
filter. Fill inlet line from reservoir to pump. Ensure M14 plug in control is closed after filling.
6. Disconnect the pump from all control input signals.
7. Close M14 plug removed in step 4.

C Caution
After start-up the fluid level in the reservoir may drop due to system components filling. Damage tohydraulic components may occur if the fluid supply runs out. Ensure reservoir remains full of fluid
during start-up.
Air entrapment in oil under high pressure may damage hydraulic components. Check carefully for
inlet line leaks.
Do not run at maximum pressure until system is free of air and fluid has been thoroughly filtered.
8. Use a common method to disable the engine to prevent it from starting. Crank the starter for several
seconds. Do not exceed the engine manufacturer’s recommendation. Wait 30 seconds and then crank
the engine a second time as stated above. This operation helps remove air from the system lines.
Refill the reservoir to recommended full oil level.
9. When the gauge begins to register charge pressure, enable and start engine. Let the engine run for aminimum of 30 seconds at low idle to allow the air to work itself out of the system. Check for leaks at
all line connections and listen for cavitation. Check for proper fluid level in reservoir.
10. When adequate charge pressure is established (as shown in model code), increase engine speed tonormal operating rpm to further purge residual air from the system.

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Initial startup procedure
11. Shut off engine. Connect pump control signal. Start engine, checking to be certain pump remains inneutral. Run engine at normal operating speed and carefully check for forward and reverse control
operation.
12. Continue to cycle between forward and reverse for at least five minutes to bleed all air and flush
system contaminants out of loop.
Normal charge pressure fluctuation may occur during forward and reverse operation.
13. Check that the reservoir is full. Remove charge pressure gauge. The pump is now ready for operation.

© Danfoss | August 2024

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Service Manual
MP1
Troubleshooting
Overview
This section provides general steps to follow if you observe undesirable system conditions. Follow thesteps listed until you solve the problem. Some of the items are system specific. We reference the sectionin this manual of more information is available. Always observe the safety precautions listed in the
Introduction section and any precautions related to your specific equipment.
Safety precautions

C Caution
High inlet vacuum causes cavitation which can damage internal pump components.

W Warning
Escaping hydraulic fluid under pressure can have sufficient force to penetrate your skin causing serious
injury and/or infection. Relieve pressure in the system before removing hoses, fittings, gauges, orcomponents.

W Warning
Unintended movement of the machine or mechanism may cause injury to the technician or bystanders.
To protect against unintended movement, secure the machine or disable/disconnect the mechanism
while servicing.

C Caution
Contamination can damage internal components and void the manufacturer’s warranty. Take
precautions to ensure system cleanliness when removing and reinstalling system lines

W Warning
Hydraulic fluid contains hazardous material. Avoid contact with hydraulic fluid. Always dispose of usedhydraulic fluid according to state, and federal environmental regulations.

Electrical troubleshooting
Item

Description

ActionControl operates pump in one direction
onlyControl coil failure

Measure resistance at coil pins. Resistance should be
14.20 ohms (24V) or 3.66 ohms (12V) at 20°C [70°F].
Replace coil

No pump function

No power to controller

Restore power to controller

Erratic pump function

Electrical connection to pump is bad

Disconnect connection, check wires, reconnect wires

System Operating Hot
Item

Description

ActionOil level in reservoir

Insufficient hydraulic fluid will not meet cooling demandsof system.

Fill reservoir to proper level.

Heat exchanger

Heat exchanger is not sufficiently cooling the system.

Check air flow and input air temperature for heatexchanger. Clean, repair or replace heat exchanger.

Charge pressure

Low charge pressure will overwork system.

Measure charge pressure. Inspect and adjust or replacecharge relief valve. Inspect charge pump. Repair or replacecharge pump.

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Troubleshooting
Item

Description

ActionCharge pump inlet vacuum

High inlet vacuum will overwork system. A dirty filter will
increase the inlet vacuum. Inadequate line size will restrict
flow.

Check charge inlet vacuum. If high, inspect inlet filter andreplace as necessary. Check for adequate line size, length orother restrictions.

System relief pressure
settings

If the system relief valves are worn, contaminated, or valve
settings are too low, the relief valves will be overworked.

Verify settings of high pressure relief valves and replacevalves as necessary.

System pressure

Frequent or long term operation over system relief setting
will create heat in system.

Measure system pressure. If pressure is too high, reduceloads.

Transmission Operates Normally in One Direction Only
Item

Description

ActionOpen bypass valves

Open bypass causes one or both directions to be
inoperative.

Close/repair bypass function.

Input to pump control

Input to control module is operating improperly.

Check control input and repair or replace as necessary.

Control orifices

Control orifice(s) are blocked.

Clean control orifices.

High pressure relief valves(HPRV)

Malfunctioning HPRV can affect one direction while theother functions normally.

Exchange HPRVs. If the problem changes direction, replace
the valve that does not operate correctly. Remember toreturn HPRVs to their original position afterward. Settings
may be different for forward/reverse.

Servo pressure

Servo pressure low or decaying.

Check for torn/missing servo seals. Replace and retest.
Refer to AX201386485461 MP1 Repair Instructions for seal
locations. Only a Danfoss Global Service Partner may
remove the servo piston without voiding the warranty.

System Does Not Operate in Either Direction
Item

Description

ActionOil level in reservoir

Insufficient hydraulic fluid to supply system loop.

Fill reservoir to proper level.

Pump control orifices

Control orifices are blocked.

Clean control orifices.

Open bypass valve

If bypass valves are open, the system loop becomesdepressurized.

Close bypass valves. Replace high pressure relief valve if
defective.

Charge pressure with pumpin neutral

Low charge pressure insufficient to recharge system loop

Measure charge pressure with the pump in neutral. If
pressure is low, go to next step.

Pump charge relief valve

A pump charge relief valve that is leaky, or contaminated,or set too low depressurizes the system.

Adjust or replace pump charge relief valve as necessary.

Charge pressure with pumpin strokeLow charge pressure, resulting from elevated loop leakage, Isolate pump from motor. With pump in partial stroke andis insufficient control pressure to hold pump in stroke.
engaged for only a few seconds, check pump chargepressure. Low charge pressure indicates a malfunctioning
pump. Good charge pressure indicates a malfunctioning
motor or other system component. Check motor charge
relief operation (if present).

Charge pump inlet filter

A clogged filter under supplies system loop.

Charge pump

A malfunctioning charge pump provides insufficient charge Repair or replace the charge pump.
flow.

System pressure

Low system pressure does not provide enough power tomove load.

Measure system pressure. Continue to next step.

System relief valves

Defective high pressure relief valves cause slow systempressure.

Repair or replace high pressure relief valves.

Input to control

Input is operating improperly.

Repair/replace control.

© Danfoss | August 2024

Inspect filter and replace if necessary.

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Service Manual
MP1
Troubleshooting
System noise or vibration
Item

Description

ActionReservoir oil levelLow oil level leads to cavitation.

Fill reservoir.

Aeration of the oil/pumpinlet vacuum

Air in system decreases efficiency of units and controls. Air
in system is indicated by excessive noise in pump, foamingin oil, and hot oil.

Find location where air is entering into the system andrepair leak. Check that inlet line is not restricted and is theproper size.

Cold oilIf oil is under cold conditions, it may be too viscous forproper function and pump cavitates.

Allow the oil to warm up to it’s normal operating
temperature with engine at idle speed.

Pump inlet vacuum

High inlet vacuum causes noise/cavitation.

Check that inlet line is not restricted and is the proper size.
Check filter and bypass valve.

Shaft couplings

A loose shaft coupling will cause excessive noise.

Replace loose shaft coupling. Replace pump shaft.

Shaft alignment

Misaligned shafts creates noise

Align shafts.

Charge/system relief valves

Unusual noise may indicate sticking valves. Possible
contamination.

Clean/replace valves and test pump. May be a normal
condition.

Neutral Difficult or Impossible to Find
Item

Description

ActionInput to pump control

Input to control module is operating improperly.

Disconnect input and check to see if pump comes back toneutral. If Yes, input fault, replace/repair external
controller. If No, go to next step.

Pump control neutral

Neutral set improperly.

Shunt servo gauge ports M4 and M5 together withexternal hose and see if pump comes back to neutral. If
Yes: control neutral improperly set. If no: balancetheswashplate (see Mechanical/hydraulic neutral
adjustment). If you still cannot set neutral, replace thecontrol.

Sluggish System Response
Item

Description

ActionOil level in reservoir

Low oil level causes sluggish response.

Fill reservoir.

High pressure relief valves/pressure limiter settings

Incorrect pressure settings affects system reaction time.

Adjust or replace high pressure relief valves.

Low prime mover speed

Low engine speed reduces system performance

Adjust engine speed.

Charge pressure

Incorrect pressure affects system performance

Measure and adjust charge pressure relief or replace chargepump.

Air in system

Air in system produces sluggish system response

Fill tank to proper level. Cycle system slowly for several
minutes to remove air from system.

Contaminated control
orifices

Control orifices are plugged.

Clean control orifices.

Pump inlet vacuum

Inlet vacuum is too high resulting in reduced systempressure.

Measure charge inlet vacuum. Inspect line for proper sizing.
Replace filter. Confirm proper bypass operation.

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MP1
Adjustments
Pump adjustment
This section offers instruction on inspection and adjustment of pump components. Read through theentire topic before beginning a service activity. Refer to Port locations and Gauge installation, for locationof gauge ports and suggested gauge size.
Standard Procedures

C Caution
Contamination can damage internal components and void your warranty. Take precautions to ensure
system cleanliness when removing and reinstalling system lines
1. With the prime mover off, thoroughly clean the outside of the pump.
2. If removing the pump, tag each hydraulic line. When you disconnect hydraulic lines, cap them andplug each open port to prevent contamination.
3. Ensure the surrounding area is clean and free of contaminants like dirt and grime.
4. Inspect the system for contamination.
5. Check the hydraulic fluid for signs of contamination: oil discoloration, foam in the oil, sludge, or metal
particles.
6. If there are signs of contamination in the hydraulic fluid, replace all filters and drain the hydraulicsystem. Flush the lines and refill the reservoir with the correct filtered hydraulic fluid.
7. Before re-installing the pump, test for leaks.

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Service Manual
MP1
Adjustments
Charge Pressure Relief Valve
This procedure explains how to check and adjust the charge pressure relief valve. Refer to model code
located on serial number plate for charge relief setting.
1. Install a 50 bar [1000 psi] pressure gauge in charge pressure gauge port M3. Install a 10 bar [100 psi]
gauge at case pressure port L1, L2. Operate the system with the pump in neutral (zero displacement)
when measuring charge pressure.
Listed pressures assume a pump speed of 1800 min-1 (rpm) and charge flow of 26.5 l/min [7 US gal/min]. At higher pump speeds or higher charge flows the charge pressure will rise over the rated
setting.
V100
QV110

V200
V300
V400

P108951

2. Add or remove shims (V200) until the desired setting is achieved.
3. Remove the gauges and plug the open ports.

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MP1
Adjustments
Displacement Limiter
If your pump has displacement limiters, you will find them on either servo cover. You can limit forward
and reverse displacement independently.

C Caution
Before adjusting the displacement limiter, mark the position of the servo cylinder. Be sure the servo
cylinder does not turn when setting the displacement limiter locknut.
1. Loosen the lockingnut.
2. Rotate the adjusting screw to achieve the desired displacement.
3. After establishing the desired maximum displacement setting, hold the adjusting screw while
torquing the locknut to the value shown.

Adjusting screw
Locknut

P108965

Displacement limiter adjustment data

© Danfoss | August 2024

Displacement

Locknut wrench size and torque

Adjusting scew
wrench size

Approximate displacement change
per revolution of adjusting screw

28

13 mm 23 N•m [17 lbf•ft]

4 mm

2.9 cm3 [0.18 in3]

32

13 mm 23 N•m [17 lbf•ft]

4 mm

3.3 cm3 [0.20 in3]

38

13 mm 23 N•m [17 lbf•ft]

4 mm

3.56 cm3 [0.22 in3]

45

13 mm 23 N•m [17 lbf•ft]

4 mm

4.22 cm3 [0.26 in3]

AX179786484978en-000405 | 55

Service Manual
MP1
Adjustments
EDC/HDC Neutral Adjustment
All functions of the control are preset at the factory. Adjust the pump to neutral with the pump runningon a test stand or on the vehicle/machine with the prime mover operating. If adjustment fails to givesatisfactory results, you may need to replace the control or coils. See Minor repair for details.

W Warning
Unintended movement of the machine or mechanism may cause injury to the technician or bystanders.
To protect against unintended movement, secure the machine or disable/disconnect the mechanism
while servicing.
1. Install a 50 bar [1000 psi] gauge in each of the two servo gauge ports (M4 and M5). Disconnect theexternal control input (electrical/hydraulic connections) from the control. Start the prime mover andoperate at normal speed.
2. Use a 4mm internal hex wrench to hold the neutral adjusting screw stationary while loosening thelocknut with a 13mm wrench.
3. Observe pressure gauges. If necessary, turn adjusting screw to reduce any pressure differential.
A small pressure differential of 1.5 bar [22 psi] or less is acceptable. Achieving zero differential isusually not possible.
Adjustment of the EDC/HDC is very sensitive. Be sure to hold the hex wrench steady while loosening
the locknut. Total adjustment is less than 120 degrees.
Control adjustment (EDC shown)
Adjusting screw
Locknut
Servo gauge port M5

Servo gauge port M4

P109037

4. Rotate the neutral adjusting screw clockwise until the pressure increases on the gauge. Note theangular position of the wrench. Then rotate the neutral adjusting screw counter clockwise until thepressure increases by an equal amount on the other gauge. Again note the angular position of thewrench.
The illustration shows how the cam on the adjusting pin rotates to adjust for neutral position after
the pump is re-installed.

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MP1
Adjustments
Neutral adjustment (EDC/HDC bottom view)

5

1

6

2
3
4

P109514

1. Control spool
2. Adjusting screw (cam)
3. Feedback pin
4. Maximum adjustment less than 120 deg.
5. Adjusting screw
6. Lock nut

5. Rotate the neutral adjusting screw clockwise half the distance between the wrench positions noted
above. The gauges should read the same pressure, indicating that the control is in its neutral position.
6. Hold the neutral adjusting screw stationary and tighten the lock nut. Torque to 10 Nm [7 lbf•ft]. Do
not over torque the nut.
7. When the neutral position is set, stop the prime mover, remove the gauges, and install the gauge
port plugs. Reconnect the external control input.
A small pressure differential of 1.5 bar [22 psi] or less is acceptable. Achieving zero differential isusually not possible.

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Service Manual
MP1
Adjustments
MDC Neutral Adjust
1. Install a 50 bar [1000 psi] pressure gauge in each of the two servo gauge ports (M4 and M5). Remove
all mechanical control input. Start the prime mover and operate at normal speed.
2. Reduce the torque of the locking nuts by rotating the nuts by 45 degrees with a 10 mm wrench.
3. If necessary, turn adjusting screw to reduce any existing pressure differential.
4. Rotate the neutral adjusting screw with a 5 mm internal hex bit clockwise until the pressure increases
in one of the pressure gauges. Note the angular position of the wrench. Then rotate the neutral
adjusting screw counterclockwise until the pressure increases by an equal amount on the othergauge. Again note the angular position of the wrench.
5. Rotate the neutral adjusting screw clockwise half the distance between the wrench position noted
above. The gauges should read the same pressure, indicating that the control is in its neutral position.
6. Hold the neutral adjusting screw stationary. Torque lock nuts to 8 N•m [5.9 lbf•ft]. Do not overtorquethe nut.
7. When the neutral position is set, stop the prime mover, remove the gauges, and install the gauge
port plugs. Reconnect the external control input.
A small pressure differential of 1.5 bar [22 psi] or less is acceptable. Achieving zero differential isusually not possible.
D060
10 mm
8 N•m
[5.9 lbf•ft]

Lock Nuts

Servo pressure gauge port M4
0 - 50 bar [0 - 1000 psi]
3/16 inch for 7/16, 6mm for M12
16.3-21.7 Nm (12-16 lbf･ft) for 7/16
20-28 Nm (14.8 - 20.7 lbf･ft) for M12

D015
5 mm

Servo pressure gauge port M5

0 - 50 bar [0 - 1000 psi]
3/16 inch for 7/16, 6mm for M12
16.3-21.7 Nm (12-16 lbf･ft) for 7/16
20-28 Nm (14.8 - 20.7 lbf･ft) for M12

NeutralAdjustment

P400738

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MP1
Adjustments
Mechanical/Hydraulic Neutral Adjustment

Servo Adjustment
1. Run prime mover at 1800 min-1(rpm).
2. If using a PWM signal, ensure the signal is off. Check the servo pressure gauges. Ensure the differential
between M4 and M5 is less than 1.5 bar [22 psi].
3. Unthread both servo cylinders 2-3 turns using servo can tool (Tool ID DLD-6247). This step ensures
the servo cylinders have no contact with the servo piston.
4. Stroke the pump by turning the adjusting screw (or supplying current to solenoid C1) until the servo
pressure at port M4 is 1 to 2 bar [14– 29 psi] greater than at port M5 and the system pressure gauges
indicate displacement. Pressure should be greater at port MA for clockwise rotation, or MB for
counter clockwise rotation. This also indicates the servo piston is in contact with the servo cylinder onside M5.
A small pressure differential of 1.5 bar [22 psi] or less is acceptable. Achieving zero differential isusually not possible.
5. Slowly thread the servo cylinder on the M5 side in until the system pressure differential starts todecrease. Maintain servo pressure differential between 1-2 bar [14-29 psi] during this step. Continue
turning the servo cylinder in until the system pressure differential (between ports MA/MB) is less than
1.5 bar [22 psi]. This procedure sets the servo and swashplate to mechanical neutral on the M5 side.
6. To complete setting neutral, repeat steps 1-5 but stroke the pump in the opposite direction byturning the adjusting screw in the opposite direction, or by supplying current/hydraulic pressure tosolenoid C2. Reverse gauge locations (M4 for M5, MB for MA) from those stated above since thepump is now stroking the other direction.
7. Remove all gauges and replace gauge port plugs.
Servo adjustment

Servo cylinder
locking bolt
Servo cylinder
locking plate

P108967

Verify neutral setting
1. If using a PWM signal to set mechanical neutral, check that servo pressure differential is less than 1.5
bar [22 psi].
2. To verify mechanical neutral, provide current to solenoid C1, or turn neutral adjusting screw, until the
servo pressure differential is 3 bar [43 psi]. The system pressure differential must be below 1.5 bar [22psi]. Repeat test on solenoid C2 side.
3. The current required to set the servo pressure differential to 3 bar [43 psi] should be the same foreach solenoid.
4. If using neutral adjusting screw to set mechanical neutral, reset control neutral.

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Service Manual
MP1
Adjustments
Servo Adjustment Side M4
1. Run prime mover at 1800 rpm.
2. If using a PWM signal to set mechanical neutral, start with the electronic control testing tool off (nocurrent/hydraulic pressure to either solenoid). Check to be sure the servo pressure differential is lessthan 1.5 bar [22 psi]. Reference Danfoss testing specifications TS-422 or Control Neutral Adjustment
instructions.
3. Turn neutral adjusting screw (or supply current/hydraulic pressure to solenoid C2) until the servo
pressure at port M5 is less than 1.5 bar [22 psi] greater than at port M4.
4. The system pressure differential must be greater than zero and the pressure at port A (B for clockwise
rotation) must be greater than the pressure at port B (A for clockwise rotation). This step ensures theservo is in contact with the servo cylinder on side M4.
5. Slowly turn in the servo cylinder on the M4 side until the system pressure differential starts todecrease. The servo pressure differential must be less than 1.5 bar [22 psi] during this step. Continue
turning in the servo cylinder until the system pressure differential is less than 1.5 bar [22 psi]. This
procedure sets the servo and swashplate to mechanical neutral.

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MP1
Minor repair
MP1 standard procedures and pump removal
Before working on the pump, thoroughly clean the outside. If the pump has an auxiliary pump attached,remove both pumps as a single unit. Tag and cap all hydraulic lines as they are disconnected, and plug all
open ports to ensure that dirt and contamination do not get into the system.
Contamination can damage internal components and void the manufacturer's warranty.
Take precautions to ensure system cleanliness when removing and installing system lines.
1. With the prime mover off, thoroughly clean all dirt and grime from the outside of the pump.
2. Tag, disconnect, and cap each hydraulic line connected to the pump. As hydraulic lines are
disconnected, plug each open port, to ensure that dirt and contamination do not get into the pump.
3. Remove the pump and its auxiliary pump (if applicable) as a single unit.
Be careful, do not damage solenoids and electrical connections when using straps or chains to
support the pump.
4. Ensure the work surface and surrounding area are clean and free of contaminants such as dirt andgrime.
5. Inspect the system for contamination.
6. Look at the hydraulic fluid for signs of system contamination, oil discoloration, foam in the oil, sludge,
or metal particles.
7. Before replacing the pump, replace all filters and drain the hydraulic system. Flush the system lines
and fill the reservoir with the correct, filtered hydraulic fluid.
8. Fill the pump with clean, filtered hydraulic fluid.
9. Attach the pump to the prime mover. Torque mounting screws according to the manufacturers
recommendation.
10. Replace all hydraulic lines. Ensure the charge inlet line is filled with fluid.
EDC/HDC Control

MP1 EDC/HDC control removal
Follow the instructions for safe removal of the EDC/HDC control.
1. Using a 5 mm internal hex wrench, remove the six cap screws (D250).
2. Remove the control module and gasket (D150). Discard the gasket.
3. If necessary, remove orifices (F00A and F00B) using a 3 mm internal hex wrench. Tag and number
them for re-installation.
If dowel pins (D300) are removed, ensure they are replaced before re-installing the control.

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Service Manual
MP1
Minor repair
MP1 EDC/HDC control identification
EDC

D250

HDC

D250

D084
D084

D098

D150

D150

D300 (2x)

F00B

F00A

P109513

Item

Description

Wrench size

Torque

D150

Control gasket

-

-

D300

Dowel pins

-

-

D250

Cap screw

5 mm internal hex

13 Nm [9.8 lbf•ft]

F00B

Servo orifice

3 mm internal hex

7.9 Nm [5.8 lbf•ft]

F00A

Servo orifice

3 mm internal hex

7.9 Nm [5.8 lbf•ft]

Controls inspection
Inspect the machined surfaces on the control pump housing. Inspect plastic PC board housing and its
sealing areas. If any damage is found, replace the damaged components.
Controls are available as a complete unit. Do not disassemble the control.
MP1 EDC/HDC control assembly
Ensure you install dowel pins (D300) in the housing before installing the control.
1. Install a new gasket (D150).
2. Install dowel pins (D300) in the housing.

W Warning
If the feedback pin comes off during operation, the pump will lose control and cause a potentiallyhazardous situation. Ensure feedback pin is properly torqued before continuing with reassembly.
3. EDC only -If the screen (D084) was removed, install a new one. Install it with the mesh facing
outward. Install retaining ring (D098).

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MP1
Minor repair
4. HDC only - If the screen (D084) was removed, install a new one. Install it with the mesh facing inward.
Screen orientations for EDC and HDC

HDC only

EDC only
D084

D084

5. Install the control module and six cap screws (D250).
Torque sequence
2

1

6

5

4

3

6. Using a 5 mm internal hex wrench, torque the cap screws (D250) to 13.3 Nm [9.8 lbf ft].

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Service Manual
MP1
Minor repair
MP1 control solenoids/actuator housing replacement
1. Disconnect electrical/hydraulic connection and remove the three cap screws (D050) using a 4 mm
internal hex wrench.
2. Remove the solenoid/actuator housing (D025/QD77) and O-ring (D025A/QD26). Discard the O-ring.
Individual coils may be replaced. Use a 12 point 26 mm socket. Torque the coil nut to 5 N•m [3.7lbf•ft].
3. Inspect the machined surface on the control. If you find any nicks or scratches, replace thecomponent.
4. Lubricate new O-ring (D025A/QD26) using petroleum jelly and install.
5. Install solenoid/actuator housing with three cap screws (D050) using a 4 mm internal hex wrench.
Torque screws to 5 N•m [4 lbf•ft].
6. Reconnect electrical/hydraulic connections and test the pump for proper operation.
MP1 control solenoid identification
Control solenoid removal

EDC

HDC
D050 (3X)
QD77
D025

QD26
QD72

D025A
D050

QD72

D025A

QD26

D025

QD77

D050 (3X)

D050

P109511

Identification and torqueItem

64 | © Danfoss | August 2024

Description

Wrench size

Torque

D025

Solenoid

-

-

D025A

O-ring--D050

Cap screw

4 mm

8 Nm [6 lbf•ft]

QD26

O-ring--

QD77

Actuator housing

-

-

QD72

Actuator pin--

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Service Manual
MP1
Minor repair
MDC Control

MP1 MDC control removal
Follow the steps to safely remove the MDC control.
1. Use a 5 mm internal hex wrench to remove the six cap screws (D250).
2. Remove the control module and gasket (D150) and discard the gasket.
3. Optional: If necessary, remove servo orifices (F00A, F00B), supply orifice (F00P), and tank orifices(F00T) using a 3 mm internal hex wrench.
It is recommended to tag the orifices for an easier re-installation process.
The functionality of the control and the neutral position of the pump may be lost if the control isdisassembled.
Do not disassemble the control module.
Before removing the control, note the position of the control lever for reassembly.

MDC Illustration
Y500

D065

Y510

MDC with CCO
D065

D250

D250

QD75
QD73

QD81
QD70
MDC with neutral start switch
D065

F00T (2x)

D250

D150
QD751
QD75
D300 (2x)
MDC with neutral start switch and CCO
D250
D065

F00B

QD751
QD75

F00P

QD81
F00A

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QD70

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Service Manual
MP1
Minor repair
MDC Legend
Wrench size and torque
Item

Description

Wrench size

TorqueD065

O-ring plug

3/16

12 N•m [9 lbf•ft]

D250

cap screw

5 mm

13.3 Nm [9.8 lbf•ft]

QD70

solenoid

-

-

QD81

O-ring--

QD75

neutral start switch assembly

-

-

QD751

O-ring

-

-

QD73

plug

3/4 inch

F00A

servo orifice

7/16 inch

F00B

servo orifice

7/16 inch

7.9 Nm [5.8 lbf•ft]

F00P

supply orifice

1/4 inch

14 Nm [10.8 lbf•ft]

F00T

tank orifice

3 mm

2.5 Nm [1.8 lbf•ft]

Y020

cap screw

5 mm

13.3 Nm [9.8 lbf•ft]

7.9 Nm [5.8 lbf•ft]

Controls inspection
Inspect the machined surfaces on the control pump housing. Inspect plastic PC board housing and its
sealing areas. If any damage is found, replace the damaged components.
Controls are available as a complete unit. Do not disassemble the control.
MDC Control Assembly
Ensure you install dowel pins (D300) in housing before installing control.
The pump will lose control, causing a potentially hazardous situation.
If a feedback pin comes off during operation, ensure the feedback pin is properly torqued before
continuing with reassembly.
1. Install a new gasket (D150).
2. If you removed screen (D084), install a new one with the mesh facing outward.
3. Install retaining ring (D098).
Proper screen orientation

D098
D084

Correct screen
orientation

D084

Incorrect screen
orientation

Remove plug on top of control to ensure the swashplate feedback pin is properly positioned in thecenter of the control module when installing control.

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MP1
Minor repair
4. If previously removed, install orifices using a 3 mm internal hex wrench and torque to 2.5 N•m [1.8lbf•ft].
5. Install the control module and six cap screws (D250).
6. Using a 5 mm internal hex wrench, torque the cap screws (D250) to 13.3 N•m [9.8 lbf•ft].
Torque sequence12© Danfoss | August 2024

6

5

4

3

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Service Manual
MP1
Minor repair
Automotive control
Automotive control removal
1. Drain pump completely before removing control. Disconnect and remove wiring (D640).
2. Fabricate a special tool to remove two plastic plugs (D610). See drawing below for tool dimensions.
Push down on plug and turn 45 degrees counterclockwise. Discard plugs.
Wax seals will be destroyed when the plugs are removed. Do not damage the housing in the plugsealing area.
3. Use a 5 mm internal hex to remove two screws (D674). Remove shield (D672).
4. Use a 5 mm internal hex to remove six screws (D250).Remove control from pump.
5. Remove and discard gasket (D150).
Alignment pins are pressed into control. Do not remove them.
6. If necessary, use a 3 mm hex wrench to remove orifices (F00A, F00B) from housing. Tag each orifice
for re-installation. Each orifice may be a different size.
7. If it is necessary to remove the screens (D084), drill out screen retention ring (D098) and remove anddiscard screen. Note screen orientation for proper reassembly.

W Warning
Do not allow metal fragments to fall into control housing. This may cause erratic pump operation.
Specialtool

Plug

Drill out retention ring

ScreenRetention
Ring

45 deg.

Ø 9.22 mm
Ø 14 mm
Ø 1.7 mm (x3)

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P108021

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Service Manual
MP1
Minor repair
Remove control
Security
wax seal (2X)
D610 (2X)
D610A (2X)
D250
5 mm
(6X)

D672

D674

D084

D150

D098

F00A

3 mm F00B

Controls inspection
Inspect the machined surfaces on the control pump housing. Inspect plastic PC board housing and its
sealing areas. If any damage is found, replace the damaged components.
Controls are available as a complete unit. Do not disassemble the control.
Automotive control installation
1. If previously removed, install new screen (D084) in original orientation. Press in new retention ring
(D098). Be sure screen will not move axially in bore after retention ring is installed.

W Warning
Failure to install screen will result in erratic pump operation.
2. If previously removed, use a 3 mm hex wrench to install orifices (F00A, F00B) in original orientation.
Torque to 5 N•m [1.8 lbf•ft].
3. Install new gasket (D150) to bottom of control.
4. Install control on pump. Use a 5 mm hex wrench to install six screws (D250). Torque to 13.3 N•m [9.8lbf•ft]. Follow torque sequence shown in gwa1450814089626.xml.
Do not damage the plastic housing when installing the screws.
5. Connect wiring (D640).
6. Use the specially fabricated tool to install new plastic plugs with O-rings (D610). Press in and turn 45
degrees clockwise.
If control will continue to be under warranty, install new sealing wax. Pumps without sealing wax
installed will not be warrantied.
7. Install protection bracket (D672). Install screws (D674). Torque to 5 N•m [3.7 lbf•ft].
If pump has been rebuilt or a new control is being installed, control software must be re-calibrated.
Refer to Automotive Control User Manual for re-calibration instructions.

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Service Manual
MP1
Minor repair
Install control
Security
wax seal (2X)
D610 (2X)
D610A (2X)
D250
5 mm
(6X)

D672

D674

D084
D098

D150

F00A

3 mm F00B

Special plug installation toolSpecialtool

Plug

45 deg.

Ø 9.22 mm
Ø 14 mm
Ø 1.7 mm (x3)

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MP1
Minor repair
Charge Pump
If the pump has an auxiliary pump attached, remove the auxiliary pump and connecting shaft before
removing the auxiliary pad.
MP1 charge pump removal
1. Position pump so end cover or auxiliary pad (K100) is on top.
2. Remove end cover/auxiliary pad screws (K300) using an 8 mm internal hex wrench.
3. Remove and discard O-ring (K200).
4. Remove coupling (K500). Use a small hook if necessary.
5. Remove the charge pump (K400).

MP1 charge pump torque information
Charge pump removal (38/45 shown)

K300
K100

K500

K400

K200

P108949

Identification and torque© Danfoss | August 2024

Item

Wrench size

TorqueScrew (K300)

8 mm

111 N•m [81.9 lbf•ft]

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Service Manual
MP1
Minor repair
MP1 charge pump inspection
Inspect the components for wear, scratches or pitting. Scratches on these components will cause aloss of charge pressure. If any component shows signs of wear, scratching or pitting, replace it.
MP1 charge pump assembly
1. Lubricate and install charge pump (K400).
2. Install coupling (K500).
3. Lubricate and install a new O-ring (K200).
4. Install cover/aux pad (K100).
Pay attention to the orientation of the cover/pad. In the case of counterclockwise rotation, when thepump control is placed on the upper side, the CCW character on the cover should be on the upperside.
5. Install screws (K300). Torque screws per table.

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Service Manual
MP1
Minor repair
High Pressure Releif Valve (HPRV)

MP1 HPRV valve removal
Follow these steps to safely remove the high pressure relief valves.
1. Using a 5/16 inch hex wrench, remove the HPRV's (N100/M100).
2. Remove and discard the O-rings (M023) and backup rings (M022).

MP1 HPRV torque information
HPRV valves removal

28/32

N100

38/45

N100

M022

M023
M100

M100

M022

M023
M022

M022
M023
M023

P108950

Identification and torque
Item

Wrench size

TorqueHPRV Valve (N100/M100)

5/16 inch

81.0 N•m [59.7 lbf•ft]

HPRV valve inspection
Inspect the sealing surfaces in the pump for nicks or scratches. Check the high pressure relief valves
for damage. Replace any damaged components.
HPRV Valve Reassembly
1. Lubricate and install new O-rings (M022) and backup rings (M023).
2. Install the HPRV valves. Torque to the value shown in the table.
3. Operate the vehicle/machine through its full range of control to ensure proper operation. Check forleaks.

© Danfoss | August 2024

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Service Manual
MP1
Minor repair
Charge Pressure Relief Valve (CPRV)MP1 CPRV removal
Follow these steps to safely remove the charge pressure relief valves.
1. Using a 1 inch wrench, remove the CPRV plug (V100).
2. Remove and discard O-ring (QV110).
3. Use a small hook or magnet to remove washer(s) (V200), spring (V300), and seat (V400).

MP1 CPRV torque information
CPRV removal (38/45 shown)
V100
QV110

V200
V300
V400

P108951

Identification and torque
Item

Wrench size

TorqueCPRV (V100)

1 inch78.6 N•m [58.0 lbf•ft]

CPRV inspection
Inspect washer, spring, and seat. Replace charge pressure relief valve if damage is found. Inspect thesealing surfaces of the pump for nicks or scratches.
MP1 CPRV assembly
1. Install seat (V400), spring (V300), and washer (V200) into the housing.
2. Install new O-ring (QV110) onto the CPRV plug (V100).
3. Install CPRV plug in housing. Torque per table.

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Service Manual
MP1
Minor repair
MP1 loop flushing removal (28/32 pictured)
1. Using an 11/16 inch hex wrench, remove plug (L150).
2. Using a ¼ inch hex wrench, remove plug (G115).
3. Remove and discard O-ring (9Q50A).
4. Remove loop flushing spool (L100).
5. Using a 4 mm hex wrench, remove orifice (L200).
MP1 loop flushing torque information
Loop flushing removal

L200
G115

L100

L150

9Q50A
P109066

Identification and torque© Danfoss | August 2024

Item

Wrench size

TorquePlug (L150)

11/16 inch

32 N•m [24 lbf•ft]

Orifice (L200)

4 mm

7.2 N•m [5.3 lbf•ft]

Plug (G115)

1/4 inch

40 N•m [30 lbf•ft]

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Service Manual
MP1
Minor repair
MP1 loop flushing spool inspection
Inspect loop flushing spool and spring. If damage or wear is found, replace spool and spring.

P109067

Reassembly
1. Lubricate and install loop flushing spool (L100).
2. Lubricate and install new O-ring (9Q50A).
3. Using a 11/16 inch wrench, torque plug (L150) to 32 N-m [24 lbf-ft].
4. Using a 4 mm hex wrench, torque orifice (L200) to 7.2 N-m [5.3 lbf-ft].
5. Using a 1/4 inch hex wrench, torque plug (G115) to 40 N•m [30 lbf•ft].
Shaft Removal
The shaft assembly is serviceable without disassembling the pump.
1. Position the pump with the shaft pointing up.
2. Remove the first spring clip (J300).
3. Carefully remove and discard the shaft seal (J250)

C Caution
Do not damage the housing bore, shaft or bearing when removing the shaft and shaft seal.
4. Remove the second spring clip (J300).
5. Pull the shaft and bearing out of the housing.
6. Remove the retaining ring (J200). Press the bearing (J150) off the shaft (J100).
Shaft removal (38/45 shown)

J150
J300
J250
J300
J200

J150

J100

P109063

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MP1
Minor repair
Inspection
Inspect the shaft journals for wear, scratching, and pits. Check the splines for fretting; replace if
damaged. Rotate the bearing, if it does not rotate smoothly, replace it.
Shaft Reassembly
1. Press the bearing (J150) onto the shaft (J100) and replace the retaining ring (J200).
2. Install the shaft/bearing assembly into the pump.
3. Install first spring clip (J300).
4. Cover the shaft with a protective sleeve while installing the seal. Lubricate and install the seal.
5. Install the second spring clip (J300).

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Service Manual
MP1
Fastener size and torque chart
MP1 fastener size and torque
G040

28/32

G035
G030
G025

G015

G020

G010

G065

H130
G010

G070

G075

G060
G030
V100
G035

38/45
G040
D250
G065 G025

G020

G015

H130

H130

G010
E085

E090

K300
N100
G045

M100
G075

G070

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G060

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Service Manual
MP1
Fastener size and torque chart
Item

Fastener

Wrench size

Torque

D250

Electric control mounting bolt

5 mm

13 N•m [10 lbf•ft]

E085

Displacement limiter screw

4 mm

NA

E090

Displacement limiter sealnut

13 mm

23 N•m [17 lbf•ft]

H130

Front cover bolt

8 mm

64 N•m [47 lbf•ft]

K300

Rear cover/aux pad mounting bolt

8 mm

111 N•m [82 lbf•ft]

MP1 plug size and torqueItem

O-ring plug

Wrench size

TorqueG010/G035

Charge pressure gauge

6 mm or 1/4 inch

40 N•m [29.5 Ft-lbs] for 9/16
35.3 N•m [26 Ft-lbs] for M14

G030/G040

Filtration inlet/outlet

6 mm or 1/4 inch

40 N•m [29.5 Ft-lbs] for 9/16
35.3 N•m [26 Ft-lbs] for M14

G020/G025

Servo gauge (28/32)

6 mm or 3/16 inch

19 N•m [18.4 Ft-lbs] for 7/16
25 N•m [18.4 Ft-lbs] for M12

G020/G025

Servo gauge (38/45)

6 mm or 1/4 inch

40 N•m [29.5 Ft-lbs] for 9/16
35.3 N•m [26 Ft-lbs] for M14

G060/065

Case drain

12 mm or 9/16 inch

48 N•m [36 Ft-lbs]

G070/075

System gauge (28/32)

19 mm or 11/16
inch

38 N•m [28 Ft-lbs] for 9/16
24 N•m [17.7 lbf-ft] for M14

System gauge (38/45)

24 mm or 7/8 inch

81 N•m [59.7 Ft-lbs] for 3/4
67 N•m [49.4 lbf-ft] for M18

M100/N100

High pressure relief

5/16 inch

81.0 N•m [59.7 Ft-lbs]

V100

Charge pressure relief

1 inch78.6 N•m [58 Ft-lbs]© Danfoss | August 2024

AX179786484978en-000405 | 79

Products we offer:

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Cartridge valves
DCV directional control
valvesElectric converters
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Danfoss Power Solutions is a global manufacturer and supplier of high-quality hydraulic andelectric components. We specialize in providing state-of-the-art technology and solutions
that excel in the harsh operating conditions of the mobile off-highway market as well as themarine sector. Building on our extensive applications expertise, we work closely with you toensure exceptional performance for a broad range of applications. We help you and othercustomers around the world speed up system development, reduce costs and bring vehicles
and vessels to market faster.

Gear motors

Danfoss Power Solutions – your strongest partner in mobile hydraulics and mobile
electrification.

Gear pumps

Go to www.danfoss.com for further product information.

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circuits (HICs)
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We offer you expert worldwide support for ensuring the best possible solutions foroutstanding performance. And with an extensive network of Global Service Partners, we also
provide you with comprehensive global service for all of our components.

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Local address:

Hydro-Gear
www.hydro-gear.com
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www.daikin-sauer-danfoss.com

Danfoss
Power Solutions (US) Company
2800 East 13th Street
Ames, IA 50010, USA
Phone: +1 515 239 6000

Danfoss
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Krokamp 35
D-24539 Neumünster, Germany
Phone: +49 4321 871 0

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Nordborgvej 81
DK-6430 Nordborg, Denmark
Phone: +45 7488 2222

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Building #22, No. 1000 Jin Hai Rd
Jin Qiao, Pudong New District
Shanghai, China 201206
Phone: +86 21 2080 6201

Danfoss can accept no responsibility for possible errors in catalogues, brochures and other printed material. Danfoss reserves the right to alter its products without notice. This also applies to products
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All trademarks in this material are property of the respective companies. Danfoss and the Danfoss logotype are trademarks of Danfoss A/S. All rights reserved.

© Danfoss | August 2024

AX179786484978en-000405