Service Manual

H1P 045/053/060/068
Axial Piston Single Pumps

www.danfoss.com

Service Manual
H1P 045/053/060/068 Axial Piston Single Pumps

Revision history

2 | © Danfoss | December 2021

Table of revisions
Date

ChangedRev

December 2021

Added HDC control

0501

April 2021

Corrected mounting screw information

0406

June 2020

Changed document number from 'AX00000104' to 'AX152886481964' and added
caution note to start-up procedures

0405

November 2018

Major layout update.

0401

April 2018

add EDC with angle sensor

0303

March 2010

Fix Osaka address

AC

Nov. 2008 - Sep 2014 Various changes.

AB-CB

Jun 2007

AA

First edition

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Service Manual
H1P 045/053/060/068 Axial Piston Single Pumps
Contents
Introduction
Hydrostatics Servicing Overview................................................................................................................................................ 5
General Servicing Instructions.....................................................................................................................................................5
Safety Precautions............................................................................................................................................................................6
General description of H1 family hydrostatic pumps..........................................................................................................7
Design...................................................................................................................................................................................................8
H1 Single Pumps Closed Circuit Pictorial Diagram.............................................................................................................. 9
H1 system schematic.................................................................................................................................................................... 10
Operation
Pressure Limiter Valves................................................................................................................................................................ 11
Pressure Limiter Sectional View.......................................................................................................................................... 11High Pressure Relief Valve (HPRV) and Charge Check Valve.......................................................................................... 12
HPRV/Charge Check Valve Sectional View...................................................................................................................... 12
Charge Pressure Relief Valve (CPRV)....................................................................................................................................... 13
Bypass function...............................................................................................................................................................................14
System Schematic for Single Pump................................................................................................................................... 14
Electrical Displacement Control (EDC)................................................................................................................................... 15
EDC Operation........................................................................................................................................................................... 16
Hydraulic Displacement Control (HDC)................................................................................................................................. 17
HDC principle............................................................................................................................................................................. 17
HDC operation........................................................................................................................................................................... 17
Manual Override (MOR)............................................................................................................................................................... 19
Manual Displacement Control (MDC) ....................................................................................................................................20
MDC operation.......................................................................................................................................................................... 20
MDC Torque................................................................................................................................................................................21
Neutral start switch (NSS)...................................................................................................................................................... 21
Case Gauge Port M14.............................................................................................................................................................. 22
Operating Parameters
Input Speed......................................................................................................................................................................................23
System Pressure..............................................................................................................................................................................23
Servo Pressure.................................................................................................................................................................................24
Charge Pressure..............................................................................................................................................................................24
Charge Pump Inlet Pressure.......................................................................................................................................................24
Case Pressure...................................................................................................................................................................................25
External Shaft Seal Pressure....................................................................................................................................................... 25
Temperature.................................................................................................................................................................................... 25
Viscosity.............................................................................................................................................................................................25
Technical Specifications
H1 Pumps General Specification.............................................................................................................................................. 26
H1 Pumps Physical Properties ..................................................................................................................................................26
Fluid Specification......................................................................................................................................................................... 27
Fluid and Filter Maintenance Recommendations
Filtration System.............................................................................................................................................................................29
Pressure Measurements
Port Locations and Gauge Installation................................................................................................................................... 30
H1P Ports Information.............................................................................................................................................................30
Initial Startup Procedures
Unintended machine movement.............................................................................................................................................31
Start-Up Procedure........................................................................................................................................................................31
TroubleshootingHigh Inlet Vacuum......................................................................................................................................................................... 33
Unintended machine movement....................................................................................................................................... 33
Fluid Under Pressure............................................................................................................................................................... 33
Electrical Troubleshooting..........................................................................................................................................................33
Neutral Difficult or Impossible to Find................................................................................................................................... 34© Danfoss | December 2021

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H1P 045/053/060/068 Axial Piston Single Pumps
Contents
Transmission Operates Normally in One Direction Only.................................................................................................34
System Operating Hot..................................................................................................................................................................34
System Will Not Operate in Either Direction........................................................................................................................ 35
System Noise or Vibration...........................................................................................................................................................35
Sluggish System Response......................................................................................................................................................... 35
Adjustments
Standard Procedures.................................................................................................................................................................... 37
Charge Pressure Relief Valve Adjustments........................................................................................................................... 38
Pressure Limiter Adjustment..................................................................................................................................................... 39
Engaging the Bypass Function..................................................................................................................................................40
Displacement Limiter Adjustment for Single Pumps........................................................................................................42
Control Neutral Adjustment.......................................................................................................................................................43
Mechanical Neutral Adjustment...............................................................................................................................................45
Pump Setup......................................................................................................................................................................................46
Servo Adjustment.......................................................................................................................................................................... 47
Minor Repair
Standard Procedures at Removing Pump.............................................................................................................................48
EDC/HDC Control Repair............................................................................................................................................................. 49
EDC/HDC Control Installation.............................................................................................................................................. 50
Control Solenoids Repair.............................................................................................................................................................50
MDC Control Repair.......................................................................................................................................................................51
MDC Control Assembly...........................................................................................................................................................52
Angle sensor on EDC Repair.......................................................................................................................................................53
EDC with Angle Sensor Repair...................................................................................................................................................54
Automotive Control Repair........................................................................................................................................................ 56
AC Control Installation............................................................................................................................................................58
Shaft Seal, Roller Bearing and Shaft Repair...........................................................................................................................59
Charge Pump Repair..................................................................................................................................................................... 61
High Pressure Relief Valve Repair.............................................................................................................................................64
Charge Pressure Relief Valve Repair........................................................................................................................................65
Pressure Limiter Repair................................................................................................................................................................ 66
Torque Chart
Fasteners and Plugs...................................................................................................................................................................... 67
Fastener Size and Torque Chart................................................................................................................................................69
Plug Size and Torque Chart........................................................................................................................................................ 69

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H1P 045/053/060/068 Axial Piston Single Pumps
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 Servicing Instructions
Follow these general procedures when repairing this product:
Icon

Description

Remove the unit

Instructions• If necessary, remove the unit from the vehicle/machine.
• Chock the wheels on the vehicle or lock the mechanism 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.
• 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
Keep it cleanadequate.

• As with any precision equipment, keep all parts free of foreign materials andchemicals.

• Protect all exposed sealing surfaces and open cavities from damage andforeign material.

Replace O-ring,gasketSecure the unit

• If left unattended, cover the pump with a protective layer of plastic.
• Danfoss recommends that you replace all O-rings, seals and gaskets.
• Lightly lubricate all O-rings with clean petroleum jelly prior to assembly.
• For repair, place the unit in a stable position with the shaft pointing
downward.

• It will be necessary to secure the pump while removing and torquing end
covers, controls, and valves.

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H1P 045/053/060/068 Axial Piston Single Pumps
Introduction
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.
Independent Braking System
Unintended vehicle or machine movement hazard. Exceeding maximum speed may cause a loss ofhydrostatic drive line power and braking capacity.
Machine manufacturer is responsible to provide a braking system, redundant to the hydrostatictransmission, sufficient to stop and hold the vehicle or machine in the event of hydrostatic drive power
loss. The braking system must also be sufficient to hold the machine in place when full power is applied.
High Inlet Vacuum
High inlet vacuum causes cavitation which can damage internal pump components.
Manufacturer’s Warranty
Contamination can damage internal components and void the manufacturer’s warranty.
Take precautions to ensure system cleanliness when removing and installing system lines.
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.
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.
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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H1P 045/053/060/068 Axial Piston Single Pumps
Introduction
General description of H1 family hydrostatic pumps
The H1 family of closed circuit variable displacement axial piston pumps is designed for use with allexisting Danfoss hydraulic motors for the control and transfer of hydraulic power. The H1 axial piston
variable displacement pumps are of cradle swash-plate design and are intended for closed circuit
applications.
Flow direction is reversed by tilting the swash-plate to the opposite side of the neutral (zerodisplacement) position. The flow rate is proportional to the pump input speed and displacement. The
latter is infinitely adjustable between zero and maximum displacement.
H1 pumps can be used together in combination with other Danfoss pumps and motors in the overall
hydraulic system.
• Danfoss hydrostatic products are designed with 15 different displacements (cm³ [in³]):
045

053

060

068

069

078

089

100

115

130

147

165

210

250

280

45.0
[2.75]

53.8[3.28]

60.4[3.69]

68.0[4.15]

69.0[4.22]

78.0[4.76]

89.2[5.44]

101.7[6.21]

115.8[7.07]

130.8[7.98]

147.0[8.97]

165.0[10.07]211.5[12.91]251.7[15.36]280.2[17.10]•Danfoss hydrostatic products are designed with many different pressure, load-life and control
capabilities:‒ Electric Displacement Control (EDC)

‒
‒
‒
‒
‒
‒
‒
•
•
•
•

Forward-Neutral-Reverse control (FNR)
Non-Feedback Proportional Electric control (NFPE)
Automotive Control (AC)Fan Drive Control (FDC)
Manual Displacement Control (MDC)
Hydraulic Displacement Control (HDC)
Control-Cut-Off valve (CCO)High power density where all units utilize an integral electro-hydraulic servo piston assembly that
controls the rate (speed) and direction of the hydraulic flow.
Compatible with the Danfoss family of PLUS+1® micro-controllers for easy Plug-and-Perform
installation.
More compact and lightweight
Improved reliability and performance

Go to the Danfoss website or applicable product catalog to choose the components that are right foryour complete closed circuit hydraulic system.

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H1P 045/053/060/068 Axial Piston Single Pumps
Introduction
DesignThe H1 axial piston variable displacement pumps are of cradle swashplate design and are intended for
closed circuit applications.
The flow rate is proportional to the pump input speed and displacement.
The latter is infinitely adjustable between zero and maximum displacement.
Flow direction is reversed by tilting the swashplate to the opposite side of the neutral (zerodisplacement) position.
The H1 family of closed circuit variable displacement axial piston pumps is designed for use with allexisting Danfoss hydraulic motors for the control and transfer of hydraulic power. H1 pumps are compact
and high power density where all units utilize an integral electro-hydraulic servo piston assembly that
controls the rate (speed) and direction of the hydraulic flow. H1 pumps are specifically compatible with
the Danfoss family of PLUS+1™ microcontrollers for easy Plug-and-Perform™ installation.
H1 pumps can be used together in combination with other Danfoss pumps and motors in the overall
hydraulic system. Danfoss hydrostatic products are designed with many different displacement, pressure
and load-life capabilities. Go to the Danfoss website or applicable product catalog to choose thecomponents that are right for your complete closed circuit hydraulic system.
Cross section view

Servo piston

Electric displacement control
Swashplate feedback pin

Valve plate
Rear bearing

PistonCharge Pump

Slipper

Shaft seal

Shaft
Front bearing
Swashplate bearing
Swashplat e

8 | © Danfoss | December 2021

Cylinder block

P106 337E

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H1P 045/053/060/068 Axial Piston Single Pumps
Introduction
The Basic Closed Circuit
Hydraulic lines connect the main ports of the pump to the main ports of the motor. Fluid flows in either
direction from the pump to the motor and back. Either of the hydraulic lines can be under high pressure.
In pumping mode the position of the pump swashplate determines which line is high pressure as well as
the direction of fluid flow.
Case Drain and Heat Exchanger
The pump and motor require case drain lines to remove hot fluid from the system. The pump and motor
drain from the topmost port to ensure the cases remain full of fluid.
The motor case drain can connect to the lower drain port on the pump housing or it can tee into the casedrain line upstream of the heat exchanger. A heat exchanger with bypass valve cools the case drain fluid
before it returns to the reservoir.
H1 Single Pumps Closed Circuit Pictorial Diagram

Heat Exchanger
Bypass Valve

System Pressure
Reservoir

Displacement Control

Servo Pressure
Charge/Low Loop Pressure

Heat Exchanger

Suction/Case Drain/
System Return

Charge Pump

Bent Axis Variable
Displacement Motor

Servo Control
CylinderCharge Filter
Motor Swashplate

Charge Check/
High Pressure Relief Valve

Variable
Displacement
Pump

OutputShaft

Loop
Flushing
Valve
Pressure
Limiter
Valve

ChargePressure
ReliefValve
To Pump
Case

Input
Shaft
Pump Swashplate© Danfoss | December 2021

To
Motor
Case

Synchronizing
Shaft

Charge Check/High Pressure Relief Valve

P104 464E

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Introduction
H1 system schematic
System schematic H1 pump and H1 motor with EDC
M14

M6

1

2

R2

R1

C2

C1

M3 L1
F00B

L2

L2 MA

MA N

A A

F00A

n

M5
CW

max.

min.

L1
M4

B B
S L3

L4

MB

M4

M5

MB

max. 3 bar[43.5 psi]
P003 424

The schematic above shows the function of a hydrostatic transmission using an H1 axial variable displacement pump with electric
proportional displacement control (EDC) and an H1 bent axis variable displacement motor with electric proportional control (L*) andintegrated loop flushing device.

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H1P 045/053/060/068 Axial Piston Single Pumps
Operation
Pressure Limiter Valves
Pressure limiter valves provide system pressure protection by compensating the pump swash plate
position when the set pressure of the valve is reached. A pressure limiter is a non-dissipative (non heatgenerating) pressure regulating system.
Each side of the transmission loop has a dedicated pressure limiter valve that is set independently. A
pump configured with pressure limiter must have pressure limiters on both sides of the system pressureloop. The pump order code allows for different pressure settings to be used at each system port.
The pressure limiter setting is the maximum differential pressure between the high and low loops. Whenthe pressure limiter setting is reached, the valve ports oil to the low-pressure side of the servo piston. Thechange in servo differential pressure rapidly reduces pump displacement. Fluid flow from the valve
continues until the resulting drop in pump displacement causes system pressure to fall below thepressure limiter setting.
An active pressure limiter destrokes a pump to near neutral when the load is in a stalled condition. The
pump swash-plate moves in either direction necessary to regulate the system pressure, including into
stroke (overrunning) or over-center (winch payout).
The pressure limiter is optional on H1 pumps (except H1T 045/053 tandem pumps).
Pressure Limiter Sectional View

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H1P 045/053/060/068 Axial Piston Single Pumps
Operation
High Pressure Relief Valve (HPRV) and Charge Check ValveAll H1 pumps have a combination high pressure relief and charge check valve. The high pressure relief
function is a dissipative (heat generating) pressure control valve for the purpose of limiting excessive
system pressures. The charge check function replenishes the low pressure side of the working loop withcharge oil.
Each side of the transmission loop has a dedicated HPRV valve that is non-adjustable with a factory setpressure. When system pressure exceeds the factory setting of the valve, oil is passed from the highpressure system loop, into the charge gallery, and into the low pressure system loop via the charge
check.
The pump may have different pressure settings to be used at each system port. When an HPRV valve isused in conjunction with a pressure limiter, the HPRV valve is always factory set above the setting of thepressure limiter. The system pressure shown in the order code for pumps with only HPRV is the HPRV
setting.
The system pressure shown in the order code for pumps with pressure limiter and HPRV is a reflection of
the pressure limiter setting:
HPRVs are set at low flow condition. Any application or operating condition which leads to elevated HPRV
flow will cause a pressure rise with flow above the valve setting. Consult factory for application review.
Excessive operation of the HPRV will generate heat in the closed loop and may cause damage to theinternal components of the pump.
HPRV/Charge Check Valve Sectional View
HPRV and Charge Check Valve with Bypass Function (except 045/053)
Relief mode

P003 268

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H1P 045/053/060/068 Axial Piston Single Pumps
Operation
Charge Pressure Relief Valve (CPRV)The charge pressure relief valve is a direct acting poppet valve that opens and discharges fluid to thepump case when pressure exceeds a designated level. The charge pressure relief valve maintains chargepressure at a designated level above case pressure.
This level is nominally set with the pump running at 1800 min-1(rpm), and with a fluid viscosity of 32
mm²/s [150 SUS]. In forward or reverse, charge pressure will be slightly lower than in neutral position. The
model code of the pump specifies the charge pressure relief valve setting. Typical charge pressure
increase from 1.2-1.5 bar per 10 l/min [17.4-21.8 psi per 2.64 US gal/min]. For external charge flow theCPRV is set according to the table below:
CPRV flow setting for external charge supply
Tandem 045/053

Single 045/053

Single 060—165

Single 210/250/280

30 l/min [7.9 US gal/min]

15 l/min [3.9 US gal/min]22.7 l/min [6.0 US gal/min]

40.0 l/min [10.6 US gal/min]

Charge pressure relief valve© Danfoss | December 2021

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H1P 045/053/060/068 Axial Piston Single Pumps
Operation
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.
Bypass function not available for tandem pumps.
System Schematic for Single Pump
The schematic below shows the function of an H1P axial piston variable displacement pump with electric
displacement control (EDC).
M14

M6 1

2

R2

R1
C2

C1

M3 L2

MA
A

F00B F00A

M4
CW
B

M5
S

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L4

MB

P003 418E

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H1P 045/053/060/068 Axial Piston Single Pumps
Operation
Electrical Displacement Control (EDC)
An EDC is a displacement (flow) control. Pump swash plate position is proportional to the input
command and 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 swash plate, changing the pump‘s displacement from full displacement in
one direction to full displacement in the opposite direction.
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.
Electrical Displacement Control

EDC schematic, feedback from swash plate
M14
C1

C2

F00B

F00A
Feedback from
Swash plate

TP

P003 478E

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H1P 045/053/060/068 Axial Piston Single Pumps
Operation
EDC Operation
H1 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 the other. Pressure differential across the servo piston moves theswashplate.
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.
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.

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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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H1P 045/053/060/068 Axial Piston Single Pumps
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-b

Displacement

100 %

-a

"0"

100 %

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Signal pressureabP102 031E

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H1P 045/053/060/068 Axial Piston Single Pumps
Operation
Manual Override (MOR)
All controls are available with a manual override functionality, either as a standard or as an option for
temporary actuation of the control to aid in diagnostics.
Control with manual override

P003 204

MOR schematic (EDC control shown)
M14

C1

C2

F00B

F00A

T

P

Feedback from swash plate.
The MOR plunger has a 4 mm diameter and must be manually depressed to be engaged. Depressing theplunger mechanically moves the control spool which allows the pump to go on stroke. The MOR should
be engaged anticipating a full stroke response from the pump.
An o-ring seal is used to seal the MOR plunger where initial actuation of the function will require a forceof 45 N to engage the plunger. Additional actuation typically require less force to engage the MOR
plunger.
Proportional control of the pump using the MOR should not be expected.

W Warning
Unintended MOR operation will cause the pump to go into stroke; example: vehicle lifted off the ground.
The vehicle or device must always be in a safe condition when using the MOR function.
Refer to control flow table for the relationship of solenoid to direction of flow.

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H1P 045/053/060/068 Axial Piston Single Pumps
Operation
Manual Displacement Control (MDC)
A Manual proportional Displacement Control (MDC) consists of a handle on top of a rotary input shaft.
The shaft provides an eccentric connection to a feedback link. This link is connected on its one end with aporting 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 swash-plate rotation. The MDC changes the pumpdisplacement between no flow and full flow into opposite directions.
Under some circumstances, such as contamination, the control spool could stick and cause the pump tostay at some displacement.
For the MDC with CCO option the brake port (X7) provides charge pressure when the coil is energized toactivate static function such as a brake release. The X7 port must not be used for any continuous oil
consumption.
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

Pump displacement vs. control lever rotation

Displacement

100 %

"A"

-d -b
-c

-a

"0"

100 %

d

Lever rotation
a

bc

"B"

P301 752

Deadband on B side: a = 3° ±1°
Maximum pump stroke: b = 30° +2/-1°
Required customer end stop: c = 36° ±3°Internal end stop: d = 40°

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.

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Operation•••

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 TorqueDescription

Value

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]

C Caution
Volumetric efficiencies of the system will have impacts on the start and end input commands.
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).
Neutral start switch schematic
M14

M5

M4

M3
P005 702

Neutral start switch data

© Danfoss | December 2021

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

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Operation
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.

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Operating Parameters
Input Speed
Minimum
speed

is the lowest input speed recommended during engine idle condition. Operating below
minimum speed limits the pump’s ability to maintain adequate flow for lubrication andpower transmission.

Rated speed

is the highest input speed recommended at full power condition. Operating at or
below this speed should yield satisfactory product life.
Operating conditions between rated and maximum speed should be restricted to lessthan full power and to limited periods of time.

Maximum
speed

is the highest operating speed permitted. Exceeding maximum speed reduces productlife and can cause loss of hydrostatic power and braking capacity. For most drive
systems, maximum unit speed occurs during downhill braking or negative power
conditions.

W Warning
Never exceed the maximum speed limit under any operating 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 forturbo-charged and Tier 4 engines.
For more information please see Pressure and Speed Limits, BC152886484313, when determining speed
limits for a particular application.
Independent Braking System
Unintended vehicle or machine movement hazard. Exceeding maximum speed may cause a loss ofhydrostatic drive line power and braking capacity.
Machine manufacturer is responsible to provide a braking system, redundant to the hydrostatictransmission, sufficient to stop and hold the vehicle or machine in the event of hydrostatic drive power
loss. The braking system must also be sufficient to hold the machine in place when full power is applied.
System Pressure
Hydraulic unit life depends on the speed and normal operating — or weighted average — pressure thatcan only be determined from a duty cycle analysis.
System pressure is the differential pressure between high pressure system ports. It is the dominantoperating variable affecting hydraulic unit life. High system pressure, which resultsfrom high load, reduces expected life.
Applicationpressureis the high pressure relief or pressure limiter setting normally defined within theorder code of the pump. This is the applied system pressure at which the drive line
generates the maximum calculated pull or torque in the application.

Maximumworkingpressureis the highest recommended application pressure and is not intended to be acontinuous pressure. Propel systems with application pressures at, or below thispressure should yield satisfactory unit life given proper component sizing.
Application pressures above maximum working pressure will only be consideredwith duty cycle analysis and factory approval.
Pressure spikes are normal and must be considered when reviewing maximum
working pressure.

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Operating Parameters
Maximumpressureis the highest intermittent pressure allowed under any circumstances. Applications
with applied pressures between rated and maximum require factory approval withcomplete application, duty cycle, and life expectancy analysis.

Minimum low
loop pressuremust be maintained under all operating conditions to avoid cavitation.
All pressure limits are differential pressures referenced to low loop (charge) pressure.
Subtract low loop pressure from gauge readings to compute the differential.

Servo Pressure
Servo pressure is the pressure in the servo system needed to position and hold the pump on stroke. It
depends on system pressure and speed. At minimum servo pressure the pump will run at reduced stroke
depending on speed and pressure.
Minimum servo pressure at corner power holds the pump on full stroke at max speed and max
pressure.
Maximum servo pressure is the highest pressure typically given by the charge pressure setting.

Charge Pressure
An internal charge relief valve regulates charge pressure. Charge pressure supplies the control withpressure to operate the swashplate and to maintain a minimum pressure in the low side of thetransmission 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 30 l/min[7.93 US gal/min] and a fluid viscosity of 32 mm2/s [150 SUS].
The charge pressure setting is referenced to case pressure. Charge pressure is the differential pressure
above case pressure.
Minimumchargepressureis the lowest pressure allowed to maintain a safe working condition in the low side ofthe loop. Minimum control pressure requirements are a function of speed, pressure,and swashplate angle, and may be higher than the minimum charge pressure shownin the Operating parameters tables.

Maximumchargepressureis the highest charge pressure allowed by the charge relief adjustment, and which
provides normal component life. Elevated charge pressure can be used as asecondary means to reduce the swashplate response time.

Charge Pump Inlet Pressure
At normal operating temperature charge inlet pressure must not fall below rated charge inlet pressure(vacuum).

24 | © Danfoss | December 2021

Minimum charge inlet
pressureis only allowed at cold start conditions. In some applications it isrecommended to warm up the fluid (e.g. in the tank) before starting theengine and then run the engine at limited speed.

Maximum charge inlet
pressure

may be applied continuously.

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Operating Parameters
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.
The auxiliary pad cavity of axial pumps configured without integral charge pumps is referenced to casepressure. Units with integral charge pumps have auxiliary mounting pad cavities referenced to charge
inlet (vacuum).
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.
External Shaft Seal Pressure
In certain applications the input shaft seal may be exposed to external pressure. In order to prevent
damage to the shaft seal the maximum differential pressure from external sources must not exceed 0.4
bar (5.8 psi) over pump case pressure.
The case pressure limits of the pump must also be followed to ensure the shaft seal is not damaged.

C Caution
Regardless of the differential pressure across the shaft seal, the shaft seal has been known to pump oilfrom the external source (e. g. gear box) into the pump case.
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 quoted rated temperature.
The maximum intermittent temperature is based on material properties and should never be
exceeded.
Cold oil will generally not affect the durability of the transmission components, but it may affect theability of oil to flow and transmit power; therefore temperatures should remain 16 °C [30 °F] above thepour point of the hydraulic fluid.
The minimum temperature relates to the physical properties of component materials.
Size heat exchangers to keep the fluid within these limits. Danfoss recommends testing to verify thatthese temperature limits are not exceeded.
Viscosity
For maximum efficiency and bearing life, ensure the fluid viscosity remains in the recommended 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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Technical Specifications
H1 Pumps General Specification
Axial piston closed circuit variable displacement pumps of cradle swash-plate design with clockwise orcounterclockwise direction of rotation.
Pipe connections••

Main pressure ports: ISO split flange boss
Remaining ports: SAE straight thread O-ring boss

Recommended installation position
Pump installation position is discretionary, however the recommended control position is on the top orat the side with the top position preferred. If the pump is installed with the control at the bottom,
flushing flow must be provided through port M14 located on the EDC, FNR and NFPE control.
Vertical input shaft installation is acceptable. If input shaft is at the top, 1 bar case pressure must be
maintained during operation. 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 nonconformance to these guidelines.
Auxiliary cavity pressure
Auxiliary cavity pressure will be inlet pressure with internal charge pump or case pressure with external
charge supply. For reference see Operating Parameters. Please verify mating pump shaft seal capability.
H1 Pumps Physical Properties
Frame size

045/053060/068

Mounting flange

ISO 3019-1 flange 101-2 (SAE B)
Special bolt dia.

ISO 3019-1 flange 127-4 (SAE C)

Input shaft outer diameter,
splines and tapered shafts

ISO 3019-1, outer Ø22 mm -4 (SAE B, 13 teeth)
ISO 3019-1, outer Ø25 mm -4 (SAE B-B, 15 teeth)
ISO 3019-1, outer Ø32 mm -4 (SAE B, 14 teeth)
Conical keyed shaft end similar to ISO 3019-1 code 25-3
taper 1:8

ISO 3019-1, outer Ø32 mm -4 (SAE C, 14 teeth)
ISO 3019-1, outer Ø35 mm -4 (SAE C, 21 teeth)

Auxiliary mounting flangewith metric fasteners per
ISO 3019-1, shaft outer
diameter and splines

Flange 82-2, outer Ø16 mm -4 (SAE A, 9 teeth)
Flange 82-2, outer Ø19 mm -4 (SAE A, 11 teeth)
Flange 101-2, outer Ø22 mm -4 (SAE B, 13 teeth)
Flange 101-2, outer Ø25 mm -4 (SAE B-B, 15 teeth)

Flange 82-2, outer Ø16 mm -4 (SAE A, 9 teeth)
Flange 82-2, outer Ø19 mm -4 (SAE A, 11 teeth)
Flange 101-2, outer Ø22 mm -4 (SAE B, 13 teeth)
Flange 101-2, outer Ø25 mm -4 (SAE B-B, 15 teeth)
Flange 127-2, outer Ø32 mm -4 (SAE C, 14 teeth)

Suction port
Main port configuration

ISO 11926-1 – 1 5/16 -12 (SAE O-ring boss)
Ø19.0 - 450 bar split flange boss per ISO 6162, M10x1.5
ISO 11926-1 – 1 5/16 -12 (SAE O-ring boss)

Ø25.4 - 450 bar split flange boss per ISO 6162, M12x1.75

Case drain ports L1, L2, L4

ISO 11926-1 – 1 1/16 -12 (SAE O-ring boss)

Other ports

SAE O-ring boss. See installation drawings.

Customer interface threads

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Metric fasteners

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Technical Specifications
Fluid Specification
Viscosity
Intermittent1)

5 mm2/s [42 SUS]

Minimum

7 mm2/s [49 SUS]

Recommended range

12 – 80 mm2/s [66 – 370 SUS]

Maximum

1600 mm2/s [7500 SUS]

1) Intermittent = Short term t < 1 min per incident and not exceeding 2 % of duty cycle based load-life.

Temperature
Minimum 1)-40°C [-40°F]

Rated

104°C [220°F]

Recommended range2)

60 – 85°C [140 – 185°F]

Maximum Intermittent

115°C [240°F]

1) Cold start = Short term t > 3 min, p ≤ 50 bar [725 psi], n ≤ 1000 min-1 (rpm).
2) At the hottest point, normally case drain port.

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Fluid and Filter Maintenance Recommendations
To ensure optimum life perform regular maintenance of the fluid and filter. Contaminated fluid is themain cause of unit failure. Take care to maintain fluid cleanliness when servicing.
• Check the reservoir daily for proper fluid level, the presence of water, and rancid fluid odor. Fluid
contaminated by water may appear cloudy or milky or free water may settle in the bottom of thereservoir. Rancid odor indicates the fluid has been exposed to excessive heat. Change the fluid andcorrect the problem immediately if these conditions occur.
• Inspect vehicle for leaks daily. Change the fluid and filter per the vehicle/machine manufacturer's
recommendations or at intervals shown in the table. We recommend first fluid change at 500 hours.
Fluid and filter change interval

•
•
•
•

Reservoir typeMax oil change interval

Sealed2000 hours

Breather

500 hoursHigh temperatures and pressures will result in accelerated fluid aging. More frequent fluid changes
may be required.
Change the fluid more frequently if it becomes contaminated with foreign matter (dirt, water, grease,etc.) or if the fluid is subjected to temperature levels greater than the recommended maximum.
Dispose of used hydraulic fluid properly. Never reuse hydraulic fluid.
Change filters with the fluid or when the filter indicator shows it's necessary.
Replace all fluid lost during filter change.

C Caution
Hydraulic fluid contains hazardous material.
Avoid contact with hydraulic fluid. Always dispose of used hydraulic fluid according to state and federal
environmental regulations.
For further information see Danfoss publication Technical Information, Hydraulic Fluids and Lubricants,
BC0000093.

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Fluid and Filter Maintenance Recommendations
Filtration System
To prevent premature wear, ensure 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, under normal
operating conditions, is recommended.
These cleanliness levels can not be applied for hydraulic fluid residing in the component housing/case or
any other cavity after transport.
The filter may be located on the pump (integral) or in another location (remote). The integral filter has afilter bypass sensor to signal the machine operator when the filter requires changing. Filtration strategies
include suction or pressure filtration.
The selection of a filter depends on a number of factors including the contaminant ingression rate, thegeneration of contaminants in the system, the required fluid cleanliness, and the desired maintenanceinterval. Filters are selected to meet the above requirements using rating parameters of efficiency andcapacity.
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 considerably higher filter efficiency is recommended. This also applies to systems with gears or clutches
using a common reservoir.
For these systems, 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.
Filter βx-ratio is a measure of filter efficiency defined by ISO 4572. It is defined as the ratio of the numberof particles greater than a given diameter (“x” in microns) upstream of the filter to the number of theseparticles downstream of the filter.
Filtration, cleanliness level and βx-ratio (recommended minimum)© Danfoss | December 2021

Cleanliness per ISO 4406

22/18/13

Efficiency βx (charge pressure filtration)

β15-20 = 75 (β10 ≥ 10)

Efficiency βx (suction and return line filtration)

β35-45 = 75 (β10 ≥ 2)

Recommended inlet screen mesh size

100 – 125 µm

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Pressure Measurements
Port Locations and Gauge Installation
When testing system pressures, calibrate pressure gauges frequently to ensure accuracy. Use snubbers toprotect gauges. The drawing and following table show the port locations and gauge sizes needed.
Port locations
M14 O-ring plug
7/16-20 UNF-2B
use for air bleed when filling pumpGage port M4
servo pressure
7/16-20 UNF 2B

Gauge port MB
System pressure
9/16-18 UNF-2B

Remote filtration port D
7/8-14 UNF-2B

Case drain Port L4
use highest port
as outlet
1 1/16-12 UNF 2B

Port B
split flange boss
1 5/16 code 62
per ISO 6162
thread: M12
18 Min. fullthread depth

060/068
Chargeconstruction
portCharge pump inlet S
1 5/16-12 UNF 2B
Gauge port MA
System pressure
9/16-18 UNF-2B

045/053
Gauge port AM3
Charge pressure
after filter
9/16-18 UNF-2B

Remote filtration port E
7/8-14 UNF-2B
Gauge port M5 Servo pressure
7/16-20 UNF-2B

Port A
split flange boss 1 5/16 code 62
per ISO 6162 thread: M12
18 Min. full thread depth

Gauge port M3
Charge pressure
after filter
9/16-18 UNF-2B

Case drain port L2
1 1/16-12 UNF-2B

P106 232E

H1P Ports Information

30 | © Danfoss | December 2021

Port identifier

Port size

Wrench size

Pressure obtained

Gauge pressure

MA, MB,9∕

1/4 internal hex

System pressure

600 bar [10,000 psi]

L2, L411∕16–12 UNF 2B

9/16 internal hex

Case drain

10 bar [100 psi]

M3; AM3 (045/053)
Alternate

9∕

16–18 UNF 2B

1/4 internal hex

Charge pressure

M4, M5, M14

7∕ –20 UNF 2B
16

3/16 internal hex

Servo pressure

16–18 UNF

50 bar [1000 psi]

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Initial Startup Procedures
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.
Start-Up Procedure
Prior to installing the pump, inspect for damage that may have occurred during shipping.
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. Ensure pump has been thoroughly
tested on a test stand before installing on a machine.

C Caution
M12X1.75 or ½" screws with hardened washer (ASTM F436M or ISO 7089 300HV) must be used to mountthe pump. Using M14 screws may cause issues when mounting.
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 and a 50 bar [1000 psi] gauge in the charge pressure gauge port M.
4. Fill the housing by adding filtered oil in the upper case drain port.
If the control is installed on top, open the construction 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; fill inlet line fromreservoir to pump.
Use a 10-micron filler filter.
6. Disconnect the pump from all control input signals.
Do not disconnect a FDC control from control input signals. Due to the fail safe function the pumpwill stroke in case of sufficient servo pressures. During start up provide a signal to keep the pump inneutral.
7. Close construction plug removed in the 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. Checkcarefully 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.
9. Crank the starter for several seconds.

C Caution
Do not to exceed the engine manufacturer’s recommendation. Wait 30 seconds and then crank theengine a second time as stated above.
This operation helps to remove air from the system lines.
10. Refill the reservoir to recommended fluid level.
11. When the gauge begins to register charge pressure, enable and start engine.
Let the engine run for a minimum of 30 seconds at low idle to allow the air to work itself out of thesystem.
12. Check for leaks at all line connections and listen for cavitation.
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Initial Startup Procedures
13. Check for proper fluid level in the reservoir.
14. Increase engine speed to normal operating rpm to further purge residual air from the system, whenadequate charge pressure is established (as shown in model code).
15. Shut off the engine.
16. Connect pump control signal.
17. Start engine, checking to be certain pump remains in neutral. Run engine at normal operating speed
and carefully check for forward and reverse control operation.
18. Continue to cycle between forward and reverse for at least five minutes to bleed all air and flush
system contaminants out of the system loop.
Normal charge pressure fluctuation may occur during forward and reverse operation.
19. Check that the reservoir is full and remove charge pressure gauge.
The pump is now ready for an operation.

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TroubleshootingThis section provides troubleshooting steps to follow if you are having problems with your machine until
you solve the problem. Some of the troubleshooting items are system specific. Always observe the safety
precautions listed in the Introduction section and precautions related to your specific equipment.
High Inlet Vacuum
High inlet vacuum causes cavitation which can damage internal pump components.
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.
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.
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.
Electrical Troubleshooting
Electrical troubleshooting
Item

Description

ActionControl operates pump in
one direction only.

Control coil failure• Measure resistance at coil pins. Resistance should be
14.20 Ω (24V) or 3.66 Ω (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.

Filter bypass indicator switch Filter switch may be bad.

• Check/replace filter switch.
• Add gauge to filter bypass port to verify proper fluid flow
and verify switch operation by measuring resistance.

‒ Open resistance ≥ 510 Ω‒ Closed resistance ≤ 122 Ω

Use a manual override to check proper pump operation and verify electrical problem, if available.

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Troubleshooting
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 or repair external controller• If No – go to next step

NeutralNeutral set improperl

Shunt servo gauge ports (M4 and M5) together withexternal hose and see if pump comes back to neutral.
• If Yes – Control neutral improperly set (see Control
Neutral Adjustment on page 43).
• If neutral is still impossible to set, balance the swashplate(see Mechanical Neutral Adjustment on page 45).
• If you still cannot set neutral, replace the control.

Transmission Operates Normally in One Direction Only
Item

Description

ActionInput 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.

Control screens

Control screen(s) are blocked.

Replace control screens. Only a Danfoss Authorized Service
Center may remove the unit’s endcap without voiding thewarranty.

Exchange system pressure
limiters

Exchanging the pressure limiter valves will show if the
problem is related to the valve function.

If the problem changes direction, replace the valve that
does not operate correctly.

Exchange high pressure
relief valves

Exchanging the high pressure relief valves will show if the
problem is related to the valve function.

If the problem changes direction, replace the valve that
does not operate correctly.

Servo pressure low or
decaying

Damaged servo seals may prevent servo piston fromstroking the pump.

Check for torn/missing servo seals. Replace and retest. Onlya Danfoss Authorized Service Center may remove the servo
piston without voiding the warranty.

Bypass function open

Open bypass will cause one or both directions to be
inoperative.

Close bypass function.

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

Charge pressure

Low charge pressure will overwork system.

Charge pump inlet vacuum

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

• Clean, repair or replace heat exchanger• Measure charge pressure.
• Inspect and adjust or replace charge relief valve.
• Inspect charge pump; repair or replace charge pump.
• Check charge inlet vacuum. If high, inspect inlet filter
and replace as necessary• Check for adequate line size, length or other 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 pressure limiters and high pressure relief
valves and adjust or replace valves 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.

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Troubleshooting
System Will 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.

Pump control screens

Control screens are blocked.

Replace control screens. Only a Danfoss Authorized Service
Center may remove the unit’s endcap without voiding thewarranty.

Bypass function open

If bypass function is open, the system loop will be
depressurized.

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

Low charge pressure withpump in neutral

Low charge pressure insufficient to recharge system loop.

Measure charge pressure with the pump in neutral. If
pressure is low, go to Pump charge relief valve.

Low charge pressure withpump in stroke

Low charge pressure resulting from elevated loop leakage.
Insufficient control pressure to hold pump in stroke.

Deadhead the pump to isolate it from the motor.Withpump in partial stroke and engaged for only a few seconds,
check pump charge pressure. Low charge pressure
indicates a malfunctioning pump. Continue to next step.
Good charge pressure indicates a malfunctioning motor orother system component. Check motor charge relief
operation (if present).

Pump charge relief valve

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

Adjust or replace pump charge relief valve as necessary.

Charge pump inlet filter

A clogged filter will under supply system loop.

Inspect filter and replace if necessary.

Charge pump

A malfunctioning charge pump will provide insufficientcharge flow.

Repair or replace the charge pump.

System pressure

Low system pressure does not provide enough power tomove load.

Measure system pressure. Continue to next step.

High pressure relief orpressure limiter valves

Defective high pressure relief or pressure limiter valvescause system pressure to be low.

Repair or replace high pressure relief or pressure limiter
valves.

Input to control

Input operating improperly

Repair/replace control.

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.
Excessive noise, foaming oil, and hot oil all indicate air in
system.

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

Cold oilIf oil is cold, it may be too viscous for proper function andpump cavitates.

Allow the oil to warm up to its 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 of proper size.
Check filter and bypass switch.

Shaft couplings

A loose shaft coupling will cause excessive noise.

Replace loose shaft coupling..

Shaft alignment

Misaligned shafts create noise.

Align shafts.

Charge/system relief valves

Unusual noise may indicate sticking valves and possible
contamination.

Clean/replace valves and test pump.

System Noise or Vibration

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.

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H1P 045/053/060/068 Axial Piston Single Pumps
Troubleshooting
Item

Description

ActionLow 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.

Contaminated control
screens

EDC supply screen is plugged.

Replace control screens. Only a Danfoss Authorized Service
Center may remove the unit’s endcap without voiding thewarranty.

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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Adjustments
This section offers instruction on inspection and adjustment of pump components. Read through theentire topic before beginning a service activity.
Refer to Pressure Measurements on page 30 for location of gauge ports and suggested gauge size.
Standard Procedures
1. Ensure the surrounding area is clean and free of contaminants like dirt and grime.
2. With the prime mover off, thoroughly clean the outside of the pump.
3. Tag each hydraulic line, if removing the pump.
4. When you disconnect hydraulic lines, cap them and plug each open port to prevent contamination.
5. Inspect the system for contamination.
6. Check the hydraulic fluid for signs of contamination: oil discoloration, foam in the oil, sludge, or metal
particles.
7. If there are signs of contamination in the hydraulic fluid, replace all filters and drain the hydraulicsystem.
8. Flush the lines and refill the reservoir with the correct filtered hydraulic fluid.
9. Before re-installing the pump, test for leaks.
Manufacturer’s Warranty
Contamination can damage internal components and void the manufacturer’s warranty.
Take precautions to ensure system cleanliness when removing and installing system lines.

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H1P 045/053/060/068 Axial Piston Single Pumps
Adjustments
Charge Pressure Relief Valve Adjustments
Operate the system with the pump in neutral (zero displacement), when measuring charge pressure.
This procedure explains how to check and adjust the charge pressure relief valve.
Charge Pressure Adjustment
Optional construction port M14

Case drain port L4

0 - 10 bar [0 - 100 psi]
3/16 in

0 - 10 bar [0 - 100 psi]
3/8 in (069/078) /9/16 in (089/100/147/165)
5/8 in (210/250/280)
70 N•m [52 lbf•ft]

12 N•m [9 lbf•ft]

Locknut
13 mm
12 N•m
[9 lbf•ft]

Case drain port L2
0 - 10 bar [0 - 100 psi]
9/16 (069/078) / 5/8 in (147/165/210/250/280)
70 N•m [52 lbf•ft] (078)
150 N•m [110 lbf•ft] (147/165/210/250/280)

Adjustment
screw
5 mm

Charge pressure gauge port M3
0 - 50 bar [0 - 1000 psi]
1/4 in24 N•m [18 lbf•ft]

1. Install a 50 bar [1000 psi] pressure gauge in charge pressure gauge port M3.
2. Install a 10 bar [100 psi] gauge at case drain port L2 or L4.
The table below shows the acceptable actual pump charge pressure range for some nominal CPRV
settings (refer to model code located on serial number plate).
Charge Pressure Range according to model code
Code

20

24

26

30

Actual chargepressure, bar [psi]20 ± 1.5[290 ± 21.8]

24 ± 1.5[348 ± 21.8]

26 ± 1.5[377 ± 21.8]

30 ± 1.5[435 ± 21.8]

The factory set pressures at 1800 min-1 (rpm) pump speed and a reservoir temperature of 50°C
[120°F], and are referenced to case pressure. At higher pump speeds with higher charge flows the
charge pressure will rise over the rated setting. Depending on the pressure rating, the chargepressure relief valve may have one or two springs.
3. Loosen the locknut and turn the adjusting screw clockwise to increase the setting, andcounterclockwise to decrease it.
The approximate adjustment per turn
Number of springs

Change per turn

1 Spring

consult factory

2 Springs

3.9 bar [56.6 psi]

4. Torque locknut to 12 N•m [9 lbf•ft], while holding the adjusting screw.
5. Remove the gauges and plug the ports, when the desired charge pressure setting is achieved.

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H1P 045/053/060/068 Axial Piston Single Pumps
Adjustments
Pressure Limiter Adjustment

W Warning
Pumps with only HPRV valves no longer contain pressure limiter screens and retainers. To convert suchpumps to those with pressure limiter valves, please contact your Danfoss service partner.
H1P Base Models with pressure setting option B include PL screens and retainers.
Lock motor output shaft to adjust the pressure limiter setting. Lock the vehicle's brakes or rigidly fix thework function so it cannot rotate.
Pressure limiter adjustment
System pressure gauge port MB

Pressure limiter
adjusting screw

0 - 600 bar [0 - 10,000 psi]
1/4 in24 N•m [18 lbf•ft]

Pressure limiterlocknut

System pressure gauge port MA(on bottom)
0 - 600 bar [0 - 10,000 psi]
1/4 in24 N•m [18 lbf•ft]

HPRV

P104 465E

Charge pressure gauge port M3
0 - 50 bar [0 - 1000 psi]
1/4 in24 N•m [18 lbf•ft]

Endcaps are different for clockwise and counter clockwise rotation.
Clockwise and counter clockwise rotation
Clockwise rotation
Pressure limiter valves
Controls
Port ACounterclockwise rotation
Pressure limiter valves
Controls
Port B

Controls
Port B

Controls
Port APort B
Systempressure

Port B
Systempressure**

Port A
Systempressure* Clockwise rotation as seen fromshaft end of pump

Port A
Systempressure* Counterclockwise rotation as seenfrom shaft end of pump

If you change pressure limiter settings, you must also change the HPRV valve to maintain proper PLfunction. Refer to table below for corresponding settings.
Pressure limiter setting (bar)© Danfoss | December 2021

PL setting

150

180

200

230

250

280

300

330

350

380

400
410
420

430
440
450

460
470
480

HPRV
setting

200

230

250

280

300

330

350

380

400

420

450

480

510

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H1P 045/053/060/068 Axial Piston Single Pumps
Adjustments
1. Install 600 bar [10 000 psi] pressure gauges in the high pressure gauge ports (MA and MB).
2. Install a 50 bar [1000 psi] pressure gauge in the charge pressure gauge port (M3).
Ensure charge pressure is properly set before checking pressure limiter.
3. Start the prime mover and operate at normal speed.
4. Use a 14 mm wrench to loosen the locking nut (L024).
5. Activate the control input until pressure in the high side of the system loop stops rising. This pressureis the PL setting.
6. Return the pump to neutral and adjust the PL setting using a 6 mm internal hex wrench .
7. Turn the adjusting screw clockwise to increase the PL setting, counter clockwise to decrease it.
The adjustment is very sensitive. Change per turn is 90 bar [1305 psi].
The model code on the serial plate gives the factory setting of the PL (Pressure Limiter). The PL setting
is referenced to charge pressure. Subtract charge pressure from system pressure gauge readings tocompute the effective PL setting.
The model code on the serial plate gives the factory setting of the PL (Pressure Limiter). The PL setting isreferenced to charge pressure. Subtract charge pressure from system pressure gauge readings tocompute the effective PL setting.
8. Repeat steps 4. and 5. until you reach the desired PL setting.
9. After adjustment, torque the lock nut (L024) to 20 N·m [15 lbf·ft].

C Caution
Do not over torque.
10. Shut down the prime mover.
11. Remove gauges and replace plugs.
Engaging the Bypass Function
It is possible to damage the drive motor(s) by operating in bypass mode without charge pressure.
Move the vehicle/machine at a speed not more than 20% of maximum for a duration not exceeding 3
minutes.
Use this procedure to bypass the pump to allow moving the vehicle/machine short distances when you
cannot start the prime mover.
Engaging the Bypass Function

HPRV
22 mm
70 N•m[52 lbf•ft]
P106 651E

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Adjustments
1. To open the HPRVs (L150), rotate three revolutions counterclockwise using a hex wrench.

C Caution
Do not rotate more than 3 revolutions, leakage will result.
2. Rotate them clockwise until seated to close the HPRVs.
See the following table for torque values:
HPRV Wrench Size and Torque Value
Frame size

Wrench size

Torque045—100

22 mm

70 N•m [52 lbf•ft]

If machine is towable with HPRVs opened three turns and if wheels are locked (not towable) with HPRV
valves closed, bypass function is working correctly.

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H1P 045/053/060/068 Axial Piston Single Pumps
Adjustments
Displacement Limiter Adjustment for Single Pumps
If your pump has displacement limiters, you will find them on either servo cover. You can limit forward
and reverse displacement independently.
Displacement limiters are not pre-set by the factory. We install them as far as possible without contacting
the servo piston. Limiting displacement requires clockwise adjustment of the limiting screw.

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.
Displacement Limiter Adjustment

Limiting Screw(see table)
Locknut(see table)

P104 469E

1. Loosen the locknut.
2. Rotate the adjusting screw to achieve the desired maximum displacement.
3. Set the adjusting screw against the servo piston by feel before counting turns.
Refer to the table for change per turn. Clockwise rotation decreases displacement, counterclockwise
rotation increases it. Adjustment is possible from zero to maximum.
Approximate displacement change cm3 [in3] per revolution
045

053

060

068

5.1 [0.31]

6.0 [0.37]

6.8 [0.41]

7.7 [0.47]

4. After establishing the desired maximum displacement setting, hold the adjusting screw while
torquing the locknut to the value in the table below.
Displacement Limiter Adjustment Data
Frame

045/053060/068

Locknut wrench size, torque

13 mm, 24 N•m [18 lb•ft]

Adjusting screw wrench size

4 mm

5. Test operation of the vehicle/machine to verify proper maximum speed of vehicle/work function.

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H1P 045/053/060/068 Axial Piston Single Pumps
Adjustments
Control Neutral Adjustment
All functions of the Electric Displacement Control (EDC), are preset at the factory. If necessary, adjust thepump to neutral with the pump running on a test stand or on the vehicle/machine with the prime mover
operating. If adjustment fails to give satisfactory results, you may need to replace the control or coils. See
Minor repair for details.
Control neutral adjustment

Servo pressure gauge port M

Adjusting screw
4 mm

Locknut
13 mm
12 N•m [9 lbf•ft]

0 - 50 bar [0 - 1000 psi]
/16 in19 N•m [14 lbf•ft]

Servo pressure gauge port M5

0 - 50 bar [0 - 1000 psi]
/16 in19 N•m [14 lbf•ft]

P106 343E

1. Install a 50 bar [1000 psi] gauge in each of the two servo gauge ports (M4 and M5).
2. Disconnect the external control input (electrical connections) from the control.
3. Start the prime mover and operate at normal speed.
4. Use a 4 mm internal hex wrench to hold the neutral adjusting screw (D015) stationary whileloosening the locknut (D060) with a 13 mm wrench.
5. Observe pressure gauges and if necessary, turn adjusting screw (D015) to reduce pressure differential.
Adjustment of the EDC is very sensitive. Be sure to hold the hex wrench steady while loosening thelocknut. Total adjustment is less than 120 degrees.
Neutral Adjustment (EDC) (bottom view)
Solenoid shaft
Control spool

Feedback pin

Adjusting
screw
(cam)

Maximum
adjustment
less than 120°
P106 046E

Illustration shows how cam on adjusting pin rotates to adjust for neutral position after pump is reinstalled.
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H1P 045/053/060/068 Axial Piston Single Pumps
Adjustments
6. Rotate the neutral adjusting screw clockwise until the pressure increases on the gauge.
Note the angular position of the wrench.
7. Rotate the neutral adjusting screw counterclockwise until the pressure increases by an equal amounton the other gauge.
Note the angular position of the wrench.
8. 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.
9. Hold the neutral adjusting screw stationary and tighten the locknut (D060). Torque to 10 N•m [9lbf•ft].

C Caution
Do not over torque.
10. When the neutral position is set, stop the prime mover and remove the gauges.
11. Install the gauge port plugs.
12. Reconnect the external control input.
A small pressure differential of 1.5 bar [22 psi] or less is acceptable. Zero differential is usually notpossible.

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Adjustments
Mechanical Neutral Adjustment
Mechanical neutral is set with the pump running at 1800 min-1(rpm). To set neutral, you must stroke thepump in each direction. The procedure is the same for each side of each pump for both the front and rear
sections.
You can do this with a small movement of the eccentric screw on EDC controls, however non-feedback
controls (NFPE/FNR) lack this mechanism. To stroke a pump with non-feedback control, you must provide
a 100 Hz PWM signal to the control solenoids. If you perform this adjustment with the pump installed in a
vehicle or machine, safely elevate the wheels or disconnect the mechanism to allow safe operation
during adjustment.
This procedure details setting neutral for the entire pump, one side at a time. Alternate M4/M5 andMA/MB to zero out forward and reverse directions of the front unit, then move the gauges to M4/M5 of
the rear unit and MC/MD (system gauge ports for the rear unit). Refer to the drawing on the next page to
identify all ports. The front and rear sections are basically mirror images of each other. The control
solenoids C1 and C2 are marked on each control.
While performing this adjustment, you monitor the following pressures:Servo pressure at M4 and M5

•
•
•
•

System pressure at MA and MB
Pressure differential between M4 and M5 (optional)
Pressure differential between A and B (optional)

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.

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H1P 045/053/060/068 Axial Piston Single Pumps
Adjustments
Pump Setup
The figure below shows the locations of system and gauge ports you use when adjusting the servo
neutral postion.
System Pressure Gauge Ports
Servo pressure
port M4

Servo pressure
port M5

Solenoid C1

SystemPort B

System Port A

Gauge port MA
system pressure

Gauge port MB
system pressure

Solenoid C2
Servo pressure
port M4
P106 489E

For more information see H1P Ports Information on page 30.
1. Attach a 50 bar [1000 psi] gauge to each servo pressure port M4 and M5.
2. Attach a 600 bar [10 000 psi] gauge to each system pressure port (MA and MB).
3. Remove servo cylinder locking screws (E350) and plates (E300) from both sides of the pump.
4. Disconnect the control solenoids from the vehicle wiring harness.
5. If using a PWM signal to set mechanical neutral, connect the control solenoids C1 and C2 to the signal
source.
Ensure the source supplies no current to the solenoids until required in the following procedure.

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Adjustments
Servo Adjustment
Servo Adjustment

E350
Servo canlocking bolt

E300
Servo canlocking plate

P106 490E

E300

Servo cylinder clamp

E350

Servo cylinder clamp bolt

1. Run prime mover at 1800 min-1 (rpm).
2. If using a PWM signal, ensure the signal is off.
3. Check the servo pressure gauges, ensure the differential between M4 and M5 is less than 2.5 bar [36psi].
4. Using a 3/4 in deep socket, unthread both servo cylinders 2-3 turns.
This step ensures the servo cylinders have no contact with the servo piston.
5. Stroke the pump by turning the control eccentric 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 pressuregauges indicate displacement.
Pressure should be greater at port MA for clockwise rotation, or MB for counterclockwise rotation.
This also indicates the servo piston is in contact with the servo cylinder on side M5.
6. Maintain servo pressure differential between 1-2 bar [14-29 psi] during this step. Slowly thread theservo cylinder on the M5 side in until the system pressure differential starts to decrease. Continue
turning the servo cylinder in until the system delta pressure results in no machine movement.
System delta pressure (ports MA to MB or MC to MD) between 3-4 bar typically does not cause
machine movement. If service of a pump is not performed on the machine, validation of machine
movement must be checked upon machine start up.
7. Repeat steps 1. to 5. but stroke the pump in the opposite direction by turning the eccentric screw inthe opposite direction, or by supplying current to solenoid C2 to complete setting neutral.
Reverse gauge locations (M4 for M5, MB for MA etc.) from those stated above since the pump is now
stroking the other direction.
8. Set neutral for the rear pump by repeating steps 1. to 6. on the rear pump. Remember that the rearpump is a mirror image of the front pump and therefore the locations of the servo gauge ports(M4/M5) and the control solenoids (C1/C2) are opposite.
9. Remove all gauges and replace gauge port plugs.
You can find wrench sizes and plug torques in the Plug Size and Torque Chart on page 69.

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H1P 045/053/060/068 Axial Piston Single Pumps
Minor Repair
Standard Procedures at Removing Pump
Before working on the pump, thoroughly clean the outside. If the pump has an auxiliary pump attached,remove both pumps as a single unit.
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.
3. As hydraulic lines are disconnected, plug each open port, to ensure that dirt and contamination do
not get into the pump.
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.
8. Flush the system lines and fill the reservoir with the correct, filtered hydraulic fluid.
9. Fill the pump with clean, filtered hydraulic fluid.
10. Attach the pump to the prime mover and torque mounting screws according to the manufacturers
recommendation.
11. Replace all hydraulic lines.
12. Ensure the charge inlet line is filled with fluid.

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H1P 045/053/060/068 Axial Piston Single Pumps
Minor Repair
EDC/HDC Control Repair
EDC control module and solenoid removal/installation

EDC

HDC
D050 (3X)

QD77

D025

QD26
QD72

D025A
D050

QD72

D025A

QD26

D025

QD77

D050 (3X)
D150
D050
F100 (2X)

D300 (2X)

1. Using a 5 mm internal hex wrench, remove the six cap screws (D250)
2. Remove the control module and gasket (D150) and discard the gasket.
3. If necessary, remove orifices (F100) using a 3 mm internal hex wrench.
Tag and number the orifices for reinstallation.
4. If screen (D084) is clogged, use a hook to remove retaining ring (D098) and screen.
5. Remove and discard screen (D084).

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H1P 045/053/060/068 Axial Piston Single Pumps
Minor Repair
EDC/HDC Control Installation
Inspect the machined surfaces on the control and top of the pump. If you find any nicks or scratches,
replace the component.
Ensure you install dowel pins (D300) in housing before installing control.
1. Install a new gasket (D150).
2. If you removed screen (D084), install a new one with the mesh facing outward.
Remove plug on top of control to ensure the swashplate feedback pin is properly positioned in thecenter of the control module when installing control.
Proper screen orientation
D084

D084

Incorrect screen
orientation

Correct screen
orientation

P106 618E

3. If previously removed, install orifices using a 3 mm internal hex wrench and torque to 2.5 N•m [1.8lbf•ft].
4. Install the control module and six cap screws (D250).
5. Using a 5 mm internal hex wrench, torque the cap screws (D250) to 13.3 N•m [9.8 lbf•ft].
Torque sequence
1

2

6

5

4

3

Control Solenoids Repair
1. Disconnect electrical connection and remove the three cap screws (D050) using a 4 mm internal hex
wrench.
2. Remove the solenoid (D025) and O-ring (D025A). Discard the O-ring.
3. If necessary, remove the coil using a 12 point 26 mm socket.
Inspect the machined surfaces on the control and top of the pump. If you find any nicks or scratches,
replace the component.
4. Lubricate new O-ring (D025A) using petroleum jelly and install.
5. Install solenoid with three cap screws (D050) using a 4 mm internal hex wrench and torque screws to
5 N•m [4 lbf•ft].
6. Install coil using a 12 point 27 mm socket and torque coil nut to 5 N•m [3.7 lbf•ft].
7. Reconnect electrical connections and test the pump for proper operation.

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Minor Repair
MDC Control Repair

D050 (3X)
4 mm

D025

D025A

D025A
D050 (3X)
4 mm

MDC Repair Legend:
D80 – Solenoid
D81 – O-ringD098 – Retaining ring
D750 – Neutral start switch
D751 – O-ring
Wrench size and torque
Item

Description

Wrench size

TorqueD065

O-ring plug

3/16 internal hex

12 N•m [9 lbf•ft]

D200

Feedback pin

13 mm deep well socket

22.5-27.5 N•m [16.6-20.3 lbf•ft]

D250

Cap screw

5 mm internal hex

13.3 N•m [9.8 lbf•ft]

D735

Plug

3/4 inch

30 N•m [22 lbf•ft]

F00A, F00B

Servo orifice

F00P

Supply orifice

3 mm internal hex

2.5 N•m [1.8 lbf•ft]

F00T

Tank orifice

1. Using a 5 mm internal hex wrench, remove the six cap screws (D250)
2. Remove the control module and gasket (D150) and discard the gasket.
3. If necessary, remove servo orifices (F00A, F00B), supply orifice (F00P), and tank orifices (F00T) using a
3 mm internal hex wrench.
Tag and number the orifices for reinstallation.
4. If screen (D084) is clogged, use a hook to remove retaining ring (D098) and screen.
5. Remove and discard screen (D084).
6. Before removing the control, note the position of the control lever for reassembly.
The functionality of the MDC control and the neutral position of the pump can be lost.
Do not disassemble the MDC control.
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H1P 045/053/060/068 Axial Piston Single Pumps
Minor Repair
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

D084

Incorrect screen
orientation

Correct 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.
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 sequence1

2

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5

4

3

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H1P 045/053/060/068 Axial Piston Single Pumps
Minor Repair
Angle sensor on EDC Repair

D767

D770

1. Clean the exterior of the pump to remove debris.
2. Remove protection cover screws (D767) using a 4 mm internal hex wrench.
3. Remove the protection cover from the control.
4. Discard the protection cover if it is damaged.
5. Remove sensor screws (D770) using a 4 mm internal hex wrench.
6. Remove and discard the sensor.
7. Position a new sensor on control housing.
8. Using a 4 mm internal hex wrench, fasten sensor to control housing with screws (D770). Torquescrews to 1.85 N•m [1.36 lbf•ft].
9. Position protection cover on control housing over sensor.
10. Using a 4 mm internal hex wrench, fasten protection cover with screws (D767). Torque screws to 1.85
N•m [1.36 lbf•ft].

W Warning
Calibration of sensor output in vehicle software is mandatory after sensor replacement because output
signal can vary from one sensor to the other.

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Service Manual
H1P 045/053/060/068 Axial Piston Single Pumps
Minor Repair
EDC with Angle Sensor Repair
D250

D150

Feedback link

Dowel pins (D300) must remain in the housing.
1. Clean pump externally with clean solvent to remove debris.
2. Using a 5 mm internal hex wrench, remove the six cap screws (D250)
3. Remove the control module and gasket (D150) and discard the gasket.
4. Install a new gasket (D150).
5. Ensure assembly fixture is positioned over the linkage spring in EDC center.
6. Position the control on the pump housing and ensure that feedback pin on swashplate is positioned
properly in control arm.

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H1P 045/053/060/068 Axial Piston Single Pumps
Minor Repair
7. Pull assembly fixture out before installing control screws.
Solenoid shaft
Control spool

Adjusting
screw
(cam)

Feedback pin
Maximum
adjustment
less than 120°

Remove plug (D065) and verify the swashplate feedback pin is properly positioned between control
feedback arms.
8. Install the control module and six cap screws (D250).
9. Using a 5 mm internal hex wrench, fasten control to pump with screws (D250).
10. Torque screws to 13.3 N•m [9.8 lbf•ft] following torque sequence shown.

Torque sequence(6 screw control)
5

4

2

1

6

3

D065

For proper neutral adjustment procedure, refer to Control Neutral Adjustment on page 43 topic.

W Warning
Calibration of sensor output in vehicle software is mandatory after sensor replacement because output
signal can vary from one sensor to the other.

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Service Manual
H1P 045/053/060/068 Axial Piston Single Pumps
Minor Repair
Automotive Control Repair
Drain pump completely before removing control.
Possible erratic pump operation.
Do not allow metal fragments to fall into control housing. Do not fail to install screen.
Security
wax seal (2X)

13.3 Nm[9.8 lbf•ft]

D610 (2X)

D250
5 mm
(6X)

D672

D674

D084

D640

D098

2.5 Nm[1.8 lbf•ft]
F00A

D150

3 mm F00B
P107 990E

1. Disconnect and remove wiring (D640).
2. Fabricate a special tool to remove two plastic plugs (D610).
See drawing below for tool dimensions.
Specialtool

Plug

45 deg.

Ø 9.22 mm
Ø 14 mm
Ø 1.7 mm (x3)
P108 021E

3. Push down on plug and turn 45 degrees counterclockwise.
4. Discard plugs.
Wax seals will be destroyed when the plugs are removed.
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H1P 045/053/060/068 Axial Piston Single Pumps
Minor Repair

C Caution
Do not damage the housing in the plug sealing area.
5. Use a 5 mm internal hex to remove two screws (D674) and remove shield (D672).
6. Use a 5 mm internal hex to remove six screws (D250) and remove control from pump.
7. Remove and discard gasket (D150).
Alignment pins are pressed into control. Do not remove them.
8. If necessary, remove orifices (F00A, F00B) using a 3 mm internal hex.
Tag and number the orifices for reinstallation.
9. If it is necessary to remove the screens, drill out screen retention ring (D098).
Drill Out Retention Ring
ScreenRetention
Ring
P108 022E

Note screen orientation for reassembly.
10. Remove and discard screen (D084).

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Service Manual
H1P 045/053/060/068 Axial Piston Single Pumps
Minor Repair
AC Control Installation
Inspect control, pump housing and plastic PC board housing, and its sealing areas.

C Caution
Do not damage the plastic housing in the plug sealing area when installing the screws.
Inspect the machined surfaces on the control and top of the pump. If you find any nicks or scratches,
replace the component.
If pump has been rebuilt or a new control is being installed, control software must be recalibrated. Refer
to H1 Automotive Control User Manual for recalibration instructions.
1. If you removed screen (D084), install a new one with the mesh facing outward.
2. Install a new retaining ring (D098).
Be sure screen will not move axially in bore after retention ring is installed.
Proper screen orientation

D098
D084

D084

Incorrect screen
orientation

Correct screen
orientation

3. If previously removed, install orifices using a 3 mm internal hex wrench and torque to 2.5 N•m [1.8lbf•ft].
4. Install a new gasket (D150).
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 sequence
1

2

6

5

4

3

7. Connect wiring (D640).
8. Install new plastic plugs with O-rings (D610) using the special tool, press plugs in and turn 45 degrees
clockwise.
If control will continue to be under warranty, install new sealing wax of a different color (original wax
is blue). Pumps without sealing wax installed will not be warrantied.
9. Install protection bracket (D672).
10. Install screws (D674). Torque to 5 N•m [3.7 lbf•ft].

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H1P 045/053/060/068 Axial Piston Single Pumps
Minor Repair
Shaft Seal, Roller Bearing and Shaft Repair
The shaft assembly is serviceable without disassembling the pump. Orient the pump on the work surface
so the shaft is pointing to the side.
Shaft assembly

Protective
sleeve

J100
J150
J200

J250
J150

J260
J275
J300

1. Unwind the spiral ring (J300) from the housing to release the shaft/seal/bearing subassembly.
2. Pry on the lip of the seal carrier (J275) to dislodge it from the pump.
3. Remove the seal carrier. Remove and discard O-ring (J260).
4. Press the seal (J250) out of the carrier and discard.
5. Pull the shaft (J100) with bearing (J150) out of the pump.
If necessary, tap lightly on the shaft to dislodge it from the cylinder block.

C Caution
Do not damage the housing bore, shaft or bearing when removing the shaft and shaft seal.
6. Remove the retaining ring (J200) using retaining ring pliers.
Press the bearing off the shaft.
7. Inspect the shaft journals for wear, scratching, and pits.
8. Check the splines for fretting; replace if damaged.
9. Rotate the bearing, if it does not rotate smoothly, replace it.
10. Press the bearing (J150) onto the shaft (J100) and replace the retaining ring (J200).
11. Ensure the retaining ring diameter is less than 38.84 mm [1.53 in] when installed on the shaft.
12. Install the shaft/bearing assembly into the pump.
13. Lubricate and install a new O-ring (J260) onto seal carrier (J275).
14. Press a new seal (J250) into the seal carrier.
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Service Manual
H1P 045/053/060/068 Axial Piston Single Pumps
Minor Repair
15. Press the seal until it is flush within +0.12mm [0.005 in] or -0.72 mm [0.0028 in] of the inside lip of thecarrier: see illustration.
Positioning seal in seal carrier
Press flush to this surface+0.12 mm [ 0.005 in] / -0.72 mm [ 0.028 in]

Seal

16. Cover the shaft with a protective sleeve while installing the seal carrier.
17. Hand press the seal carrier into the housing.
18. Ensure the seal carrier clears the spiral ring groove in the housing.
19. Remove the protective sleeve.
20. Wind the spiral ring into the housing.
21. Ensure the inside diameter of the spiral ring is greater than 68 mm [2.677 in] after installation.

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Service Manual
H1P 045/053/060/068 Axial Piston Single Pumps
Minor Repair
Charge Pump Repair
If an auxiliary pump is attached, remove auxiliary pump and coupling before servicing charge pump.
Position pump with front shaft pointing downward. Attach securely to a proper work stand.
If necessary, you must replace charge pump components (gearset, outer ring, valve and pressure balanceplates) as a kit.
Charge pump removal/installation
K400
8 mm

K100

G450

G450
K150

K500
S300

S200

K200

S100

S250

S300

E101 406E

1. Remove end cover/auxiliary pad screws (K400) using a 8 mm internal hex wrench.
Alignment pins (G450) are in the end cover. They may dislodge during disassembly.
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Service Manual
H1P 045/053/060/068 Axial Piston Single Pumps
Minor Repair
2. Remove and discard gasket (K150).
3. Remove thrust washer (K500).
Note thrust washer orientation.
4. Use a small hook to remove pressure balance plate (S200) and seal (S300); discard seal.
Note plate orientation.
5. Remove coupling (K200). Use a small hook if necessary.
6. Remove the charge pump outer ring (S150), and gearset (S100).
7. Remove valve plate (S250) with seal (S300); discard seal.
8. Inspect the components for wear, scratches or pitting.
9. Carefully inspect the valve and pressure balance plates.
Scratches on these components will cause a loss of charge pressure. If any component shows signs ofwear, scratching or pitting, replace it.
10. Install new seals (S300) in the valve (S250) and pressure balance (S200) plates.
11. Install valve plate (S250) in the same orientation as removed.
12. Lubricate and install charge pump (S100) and outer ring (S150).
13. Install charge pump coupling (K200).
14. Install pressure balance plate (S200) in the same orientation as removed.
15. Install the thrust washer (K500); coated side goes toward charge pump coupling (K200).
16. Install a new cover gasket. (K150).
17. If removed, install guide pins (K450).
18. Install the auxiliary pad or charge pump cover and cap screws.
19. Using a 8 mm internal hex wrench, torque the cap screws (K400) to 92 N•m [68 lbf•ft].
Torque sequence

1

4

3

2
P106 346E

Ensure proper torque on aux pad screws (K400) and if necessary, replace screws.
20. Reinstall auxiliary pump or pad seal (K250) and shipping cover ((K300).
If necessary, remove auxiliary pump, or shipping cover (K300) and pad seal (K250) as shown below:

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H1P 045/053/060/068 Axial Piston Single Pumps
Minor Repair
Auxilliary pads

K350
(see table)
K300

K250

K400
8 mm

SAE B

E101 533E

SAE A

Cover Screw K350

© Danfoss | December 2021

Aux. Cover Pad

Cover Pad A

Cover Pad B

Wrench size and torque

17 mm 48 N•m [35 lbf•ft]

18 mm 77 N•m [58 lbf•ft]

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Service Manual
H1P 045/053/060/068 Axial Piston Single Pumps
Minor Repair
High Pressure Relief Valve Repair

L060
L068

P106 039E

L150
see table

1. Using a hex wrench wrench shown in the table below, remove the HPRVs (L150).
2. Inspect the sealing surfaces in the pump for nicks or scratches, check the valves for damage.
3. Replace any damaged components.
4. Remove and discard the O-rings (L060) and backup rings (L068).
5. Lubricate and install new backup rings (L068) and O-rings (L060).
6. Install HPRVs, and torque to the value in the table.
Frame size

Wrench size

Torque069/078/089/100

22 mm

70 N•m [52 lbf•ft]

115/130/147/165/210/250/280

30 mm

110 N•m [81 lbf•ft]

7. Operate the vehicle/machine through full range of controls to ensure proper operation.
8. Check for leaks.

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H1P 045/053/060/068 Axial Piston Single Pumps
Minor Repair
Charge Pressure Relief Valve Repair

C Caution
Replace the charge pressure relief valve (V010) as a complete unit. Do not attempt to repair the internal
components of the valve.

V024

V010
22 mm
52 N•m[38 lbf•ft]

P106 040E

1. Using a 22 mm wrench, remove the charge pressure relief valve (V010).
2. Discard a seal (V024).
3. Inspect the sealing surfaces of the pump for nicks or scratches.
4. Lubricate and install the new seal (V024).
5. Install the charge pressure relief valve, and torque to 52 N•m [38 lbf•ft].
6. Operate vehicle/machine through full range of controls to ensure proper operation.
See for adjustment instructions.

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Service Manual
H1P 045/053/060/068 Axial Piston Single Pumps
Minor Repair
Pressure Limiter Repair

W Warning
Pumps with only HPRV valves no longer contain pressure limiter screens and retainers. To convert suchpumps to those with pressure limiter valves, please contact your Danfoss service partner.
H1P Base Models with pressure setting option B include PL screens and retainers.

C Caution
Replace the pressure limiter valve (V010) as a complete unit. Do not attempt to repair the internal
components of the valve.

L300

L400

O

L022

E101336

1. Using a 17 mm wrench, remove the pressure limiter valve (L100), and discard O-ring.
2. Inspect the sealing surfaces of the pump for nicks or scratches.
3. Install new O-ring.
O-ring is available separately.
4. Lubricate O-ring with petroleum jelly.
5. Replace pressure limiter valve and torque to 40 N·m [29 lbf·ft].
6. Operate pump at full range of controls to ensure proper machine operation.
See Pressure Limiter Adjustment on page 39 for adjustment instructions.

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H1P 045/053/060/068 Axial Piston Single Pumps
Torque Chart
Fasteners and Plugs

L200
High pressure
relief valve
V020
Charge pressureadjusting screw
V022
Charge pressure
locking nut

V10
Charge pressure
cartridge
L100
High pressure
relief valve

K400
Rear cover / auxiliary pad
mounting bolt
K350
Rear cover mounting bolt
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Service Manual
H1P 045/053/060/068 Axial Piston Single Pumps
Torque Chart
G251 O-ring plug, 9/16 - 18

B020 O-ring plug, 1-1/16 - 12
D250Electric control
mounting bolt

G300 O-ring plug, 9/16 - 18

M14 O-ring plug, 7/16 - 20
D015 Neutral adjusting screw
D060 Neutral adjust locking nut
D050 Coil mounting bolt
E350
Servo cylinder locking bolt

B020 O-ring plug, 1-1/16 - 12

68 | © Danfoss | December 2021

B015 O-ring plug, 7/16 - 20
L010 Pressure limiter adjusting screw
L024 Pressure limiter locking nut
L300/L400 Pressure limiter cartridge
G302 O-ring plug, 9/16 - 18

P106 349E

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Service Manual
H1P 045/053/060/068 Axial Piston Single Pumps
Torque Chart
Fastener Size and Torque Chart
H1P 045/053 and 060/068
Item

Fastener

Wrench size

Torque

D015

Neutral adjust screw

4 mm internal hex

NA

D050

Coil mounting bolt

4 mm internal hex

8 N•m [9 lbf•ft]

D060

Neutral adjust locking nut

13 mm

10 N•m [7 lbf•ft]

D250

Electric control mounting bolt

5 mm internal hex

13.3 N•m [9.8 lbf•ft]

E350

Servo cylinder locking bolt

11 mm

14.5 N•m [11 lbf•ft]

K350 A pad

Shipping cover mounting bolt

17 mm

8.7 N•m [6.4 lbf•ft]

K350 B pad

Shipping cover mounting bolt

18 mm

12 N•m [8.9 lbf•ft]

K400

Rear cover/aux pad mounting bolt

8 mm internal hex

92 N•m [68 lbf•ft]

L010

Pressure limiter adjust screw

6 mm

NA

L300
L400

Pressure limiter cartridge

17 mm

40 N•m [29 lbf•ft]

L024

Pressure limiter locking nut

14 mm

20 N•m [15 lbf•ft]

L100
L200

High pressure relief valve

22 mm

70 N•m [52 lbf•ft]

V10

Charge pressure cartridge

22 mm

52 N•m [38 lbf•ft]

V020

Charge pressure adjusting screw

4 mm internal hex

NA

V022

Charge pressure locking nut

13 mm

12 N•m [9 lbf•ft]

Plug Size and Torque Chart
Item

O-ring plug

Wrench size

TorqueB015

7/16–20

3/16 in internal hex

19 N•m [14 lbf•ft]

B020

1-1/16–12

9/16 in internal hex

49 N•m [36 lbf•ft]

D065

7/16–20

3/16 in internal hex

19 N•m [14 lbf•ft]

G250

9/16–18

7 mm internal hex

22–26 N•m [16–20 lbf•ft]

G300
G302

9/16–18 UNF

1/4 in internal hex

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Cartridge valves
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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.

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Danfoss Power Solutions – your strongest partner in mobile hydraulics and mobile
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Go to www.danfoss.com for further product information.

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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
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Phone: +1 515 239 6000

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© Danfoss | December 2021

AX152886481964en-000501