Service Manual

H1T 045/053, 060/068
Axial Piston Tandem Pumps

www.danfoss.com

Service Manual
H1T 045/053, 060/068 Axial Piston Tandem Pumps

Revision history

2 | © Danfoss | December 2021

Table of revisions
Date

ChangedRev

December 2021

Added HDC control

0501

September 2020

Changed document number from 'AX00000103' to 'AX152886481761' and added
important info about PL screens

0405

November 2018

Major layout update.

0401

June 2018

Angle sensor topics added.

0303

August 2017

Minor update.

0302

May 2017

Added frames H1T 060/068

0301

Oct. 2007-March 2015 Various changes.

AB-BD

Jun 2007

AA

First edition.

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Service Manual
H1T 045/053, 060/068 Axial Piston Tandem Pumps
Contents
Introduction
Hydrostatics Servicing Overview................................................................................................................................................ 5
General Servicing Instructions.....................................................................................................................................................5
Safety Precautions............................................................................................................................................................................6
Independent Braking System................................................................................................................................................. 6
High Inlet Vacuum...................................................................................................................................................................... 6
Manufacturer’s Warranty..........................................................................................................................................................6
The Basic Closed Circuit................................................................................................................................................................. 7
Case Drain and Heat Exchanger..................................................................................................................................................7
Tandem Pumps Design.................................................................................................................................................................. 8
H1T pumps pictorial diagram...................................................................................................................................................... 9
H1T Tandem Pumps Schematics..............................................................................................................................................10
System Schematic for Tandem Pumps...................................................................................................................................11
Operation
Pressure Limiter Valves................................................................................................................................................................ 12
Pressure Limiter Sectional View.......................................................................................................................................... 12High Pressure Relief Valve (HPRV) and Charge Check Valve.......................................................................................... 13
HPRV/Charge Check Valve Sectional View...................................................................................................................... 13
Charge Pressure Relief Valve (CPRV)....................................................................................................................................... 15
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) ....................................................................................................................................19
MDC operation.......................................................................................................................................................................... 20
MDC Torque................................................................................................................................................................................21
Neutral start switch (NSS)...................................................................................................................................................... 21
Case Gauge Port M14.............................................................................................................................................................. 21
Control-Cut-Off (CCO) and Brake Release Valves............................................................................................................... 21
Operating Parameters
Input Speed......................................................................................................................................................................................24
Independent Braking System...............................................................................................................................................24
System Pressure..............................................................................................................................................................................24
Servo Pressure.................................................................................................................................................................................26
Charge Pressure..............................................................................................................................................................................26
Charge Pump Inlet Pressure.......................................................................................................................................................26
Case Pressure...................................................................................................................................................................................26
External Shaft Seal Pressure....................................................................................................................................................... 27
Temperature.................................................................................................................................................................................... 27
Viscosity.............................................................................................................................................................................................27
Technical Specifications
H1 Pumps General Specification.............................................................................................................................................. 28
Technical Data for H1 Tandem Pumps...................................................................................................................................28
Operating parameters for H1 Tandem Pumps.................................................................................................................... 29
Fluid Specification......................................................................................................................................................................... 30
Fluid and Filter Maintenance Recommendations
Pressure Measurements
Port locations and gauge installation - 045/053.................................................................................................................32
Port locations and gauge installation - 060/068.................................................................................................................33
Initial Startup ProceduresStart-Up Procedure........................................................................................................................................................................34
Troubleshooting
Safety Precautions......................................................................................................................................................................... 36© Danfoss | December 2021

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Contents
High Inlet Vacuum....................................................................................................................................................................36
Unintended machine movement....................................................................................................................................... 36
Independent Braking System...............................................................................................................................................36
Manufacturer’s Warranty....................................................................................................................................................... 36
Electrical Troubleshooting..........................................................................................................................................................37
Integral Filter Bypass.....................................................................................................................................................................37
Neutral Difficult or Impossible to Find................................................................................................................................... 37
Transmission Operates Normally in One Direction Only.................................................................................................37
System Operating Hot..................................................................................................................................................................38
System Will Not Operate in Either Direction........................................................................................................................ 38
System Noise or Vibration...........................................................................................................................................................39
Sluggish System Response......................................................................................................................................................... 39
Adjustments
Standard Procedures.................................................................................................................................................................... 40
Charge Pressure Relief Valve Adjustment.............................................................................................................................41
Pressure Limiter.............................................................................................................................................................................. 44
Pressure Limiter Screens........................................................................................................................................................ 44
Pressure Limiter Adjustment (060/068 only)..................................................................................................................44
Charge check / HPRV adjustment............................................................................................................................................ 47
Engaging the Bypass Function..................................................................................................................................................48
Displacement Limiter Adjustment for Tandem Pumps................................................................................................... 49
Control Neutral Adjustment.......................................................................................................................................................51
Mechanical Neutral Adjustment...............................................................................................................................................53
Pump setup.................................................................................................................................................................................53
Servo Adjustment for Tandem Pumps................................................................................................................................... 54
Minor repair
Standard Procedures at Removing Pump.............................................................................................................................57
EDC/HDC Control Repair............................................................................................................................................................. 57
EDC/HDC Control Installation.............................................................................................................................................. 58
Control Solenoids Repair.............................................................................................................................................................59
MDC Control Repair.......................................................................................................................................................................60
MDC Control Assembly...........................................................................................................................................................61
Angle sensor on EDC Repair.......................................................................................................................................................62
EDC with Angle Sensor Repair...................................................................................................................................................63
Shaft, Seal and Bearing Repair...................................................................................................................................................65
Shaft, Seal and Bearing Installation....................................................................................................................................66
Charge Pump Repair (045/053 only).......................................................................................................................................67
Charge Pump Installation...................................................................................................................................................... 68
Charge Check and HPRV Repair (045/053)............................................................................................................................69
HPRV Port Relationship...........................................................................................................................................................70
HPRV (60/68).................................................................................................................................................................................... 71
Pressure Limiter Screens........................................................................................................................................................ 71
HPRV Repair (060/068)............................................................................................................................................................71
Charge Pressure Relief Valve Repair........................................................................................................................................73
Control Cut-off Valve / Brake Valve Repair............................................................................................................................74
Torque Chart
Fasteners and Plugs...................................................................................................................................................................... 76
Fastener Size and Torque Chart................................................................................................................................................77
Plug Size and Torque Chart........................................................................................................................................................ 78

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H1T 045/053, 060/068 Axial Piston Tandem 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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H1T 045/053, 060/068 Axial Piston Tandem 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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H1T 045/053, 060/068 Axial Piston Tandem 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.

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H1T 045/053, 060/068 Axial Piston Tandem Pumps
Introduction
Tandem Pumps Design
Danfoss H1 tandem closed circuit piston pumps convert input torque to hydraulic power. The tandem
design powers two independent drive trains for dual-path propel applications.
The two-piece input shaft transmits rotational force to the cylinder block. A splined coupling connects
the front and rear shafts. Bearings at the front, rear, and center of the pump support the shaft. Splines
connect each shaft to a cylinder block. A lip-seal at the front end of the pump prevents leakage where theshaft exits the pump housing. The spinning cylinder block contains nine reciprocating pistons. Eachpiston has a brass slipper connected at one end by a ball joint. The block spring, ball guide, and slipper
retainer hold the slippers to the swashplate. The reciprocating movement of the pistons occurs as theslippers slide against the inclined swashplates during rotation.
Via the valve plates, one half of each cylinder block is connected to port A or C and the other half to port
B or D. Front and rear sections have independent porting in the center section. As each piston cycles inand out of its bore, fluid is drawn from one port and displaced to the other thereby imparting hydraulicpower into the system. A small amount of fluid is allowed to flow from the cylinder block/valve plate andslipper/swashplate interfaces for lubrication and cooling. Case drain ports return this fluid to thereservoir. An external charge pump (not shown) provides clean, cool fluid to makeup this lubricating flow
and to maintain minimum loop pressure.
The angle of each swashplate controls the volume and direction of fluid displaced into the system. The
servo pistons control the angle of the swashplates. Each pump control, by varying the pressure at the
servo pistons, controls each piston’s position. An electric signal to the control coils transmits thecommand from the operator to the pump. Mechanical feedback of the swashplate position to the control
through the feedback pins allows for very precise displacement control and increases overall systemstability. Non-feedback control options do not use the mechanical feedback link.
Cross section view
Electric displacement control

Electric displacement control

Servo piston

Servo piston

Swashplate feedback pin

Swashplate feedback pin
Valve plates
PistonPistonSlipper
Front shaft bearing

Slipper

Rear shaft bearing

Shaft seal

Front sha ft

Rear shaft
Swashplate bearing

Shaft coupling

Swashplat e

Cylinder block

Center shaft bearings

Swashplate bearing

Cylinder block

Swashplat e
P106 146E

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H1T 045/053, 060/068 Axial Piston Tandem Pumps
Introduction
H1T pumps pictorial diagram

Charge Pressure

Servo Pressure

System Pressure

Low Loop Pressure

FilterSuctionScreenCharge Pump

Displacement Control

Suction/Case Drain/
System Return

Bypass check

Heat exchanger
Reservoir

Control
CutoffValve

Displacement Control

ChargePressure
ReliefValve
To Pump
Case
Servo Control
CylinderServo Control
CylinderTo Pump
Case

Variable
Displacement
Pump

Input
Shaft

Pump Swashplate

Pump Swashplate
Charge check /HPRV valve

Motorswashplate

Motor
servo
piston

Displacement
limiterMotorswashplat e
Motordisplacement
control valve

Outputshaft

Cylinderblockassembly© Danfoss | December 2021

Motor
servo
pistonLoop
Flushing
Valve
To
Motor
Case

Motor
displacement
control valve

Outputshaft

Loop
Flushing
Valve
To
Motor
Case

Cylinderblockassembl y
P106147

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H1T 045/053, 060/068 Axial Piston Tandem Pumps
Introduction
H1T Tandem Pumps Schematics
The schematics below show the function of an H1 tandem axial piston variable displacement pump withelectric displacement control (EDC) and optional control cut-off valve.
045/053 Tandem

C1

C2

C2
X7

C1

E
MA

MD
Flow
out A

Flow
out C

D

A

CW

CW

C

B

MC

MB
M4 M5

M3

M5 M4

L3
P106 148E

060/068 Tandem
CONTROL SOLENOID C2

CONTROL SOLENOID C2
1
2

C1

1
2
BRAKE SOLENOID

M14

1
2

CONTROL SOLENOID C1

Supply/Ground
Ground/Supply

M14

C2

C2
A

MA

M3

E

MD

1
2

Supply/Ground
Ground/Supply

Supply/Ground
Ground/Supply

Supply/Ground
Ground/Supply

1
2

Supply/Ground
Ground/Supply

CCO SOLENOID

1
2

Supply/Ground
Ground/Supply

CONTROL SOLENOID C1

C1

D

L3
flow out B

flow out D

ccw

H1 Tandem
M5

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M4

B

MB

X7

C

MC

M4

M5

L1

P109541

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H1T 045/053, 060/068 Axial Piston Tandem Pumps
Introduction
System Schematic for Tandem Pumps
The schematic below shows the function of H1T axial piston variable displacement tandem pumps withelectric displacement control (EDC).
System schematic, tandem pumps
M14
C1

M14
C1

C2

MB

X7

M3

C2

MC
L3

F00B

M5

F00B

F00A

CW

PTO

M4

M5

M4
MA A

© Danfoss | December 2021

F00A

B

E C D MD

P003 207E

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H1T 045/053, 060/068 Axial Piston Tandem 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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H1T 045/053, 060/068 Axial Piston Tandem 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

Charging mode

P003 268

P003 269

HPRV and Charge Check Valve with Bypass Function (except H1P 045/053)
Charging mode

Relief mode

1

1

2

2
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H1T 045/053, 060/068 Axial Piston Tandem Pumps
Operation
1. Low pressure side of working loop
2. Charge check and HPRV

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H1T 045/053, 060/068 Axial Piston Tandem 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:
Standard level setting is ∆p = 21 ± 1.1 bar [304 ± 16 psi] with the pump running at 1500 min-1(rpm) andflow = 23.80 - 29.5 l/min [ 6.3 - 7.8 US gal/min]. Typical charge pressure increase is 2 bar per 10 l/min [29psi per 2.64 US gal/min].
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

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.

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H1T 045/053, 060/068 Axial Piston Tandem Pumps
Operation
Electrical Displacement Control

EDC schematic, feedback from swash plate
M14
C1

C2

F00B

F00A
Feedback from
Swash plate

TP

P003 478E

P003 191

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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H1T 045/053, 060/068 Axial Piston Tandem Pumps
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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H1T 045/053, 060/068 Axial Piston Tandem 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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H1T 045/053, 060/068 Axial Piston Tandem 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.
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.
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H1T 045/053, 060/068 Axial Piston Tandem Pumps
Operation
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.

•••

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.
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Operation
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
Max. continuous current with switching

8.4 A

Max. continuous current without switching

20 A

Max. voltage

36 VDCElectrical protection class

IP67 / IP69K with mating connector

Case Gauge Port M14
The drain port should be used when the control is mounted on the unit’s bottom side to flush residual
contamination out of the control.
Control-Cut-Off (CCO) and Brake Release Valves
The H1 tandem pumps offer an optional Control-Cut-Off valve integrated into the pump center section
and a separate brake release valve allowing the controls to be activated before activating any auxiliary
functions.
The CCO valve shunts charge pressure from the pump controls allowing the servo springs to de-stroke
both pumps. The valve is normally open for fail-safe operation. The solenoid must be energized for thepump to operate. When the machine control circuits energize the CCO solenoid, it connects charge
supply from the charge gallery to the pump controls.

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H1T 045/053, 060/068 Axial Piston Tandem Pumps
Operation
The 045/053 tandem also supplies charge pressure to the port X7 for auxiliary operation of devices suchas spring applied/pressure released brakes. The control cut off valve also shunts pressure away from port
X7.
The 060/068 tandem offers a separate brake release valve that operates independently of the CCO valve
allowing the controls to be activated before activating any auxiliary functions. When the 60/68 brake
valve is deactivated the X7 port shunts to case.
045/053 Tandem

C1

C2

C2
X7

C1

E
MA

MD
Flow
out A

Flow
out C

D

A

CW

CW

B

C
MC

MB
M4 M5

M3

M5 M4

L3
P106 148E

060/068 Tandem
CONTROL SOLENOID C2

CONTROL SOLENOID C2
1
2

C1

1
2
BRAKE SOLENOID

M14

1
2

CONTROL SOLENOID C1

Supply/Ground
Ground/Supply

M14

C2

C2
A

M3

MA

E

MD

1
2

Supply/Ground
Ground/Supply

Supply/Ground
Ground/Supply

Supply/Ground
Ground/Supply

1
2

Supply/Ground
Ground/Supply

CCO SOLENOID

1
2

Supply/Ground
Ground/Supply

CONTROL SOLENOID C1

C1

D

L3
flow out B

flow out D

ccw

H1 Tandem
M5

22 | © Danfoss | December 2021

M4

B

MB

X7

C

MC

M4

M5

L1

P109541

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Operation
Solenoid data
Description

12 V

24 V

Minimum supply voltage

9 VDC

18 VDC

Maximum supply voltage (continuous)

16 VDC

32 VDCIP Rating

IEC 60 529

IP 67

DIN 40 050, part 9

IP 69K with mating connector

Pin connector

any order

For additional information, please contact Danfoss.

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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© Danfoss | December 2021

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.

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Operating Parameters
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).
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.

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.
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Operating Parameters
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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H1T 045/053, 060/068 Axial Piston Tandem Pumps
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
Main pressure ports H1P 045/053: SAE straight thread O-ring boss
Main pressure ports H1P 060/068: 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.
Technical Data for H1 Tandem Pumps
Technical Data
FeatureUnit

Displacement

cm3 [in3]

045

053

060

068

45.0 [2.75]

53.8 [3.28]

60.4 [3.69]

68.0 [4.15]

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

153 [40]183 [48]

210 [55.5]

238 [62.8]

Torque at maximum displacement(theoretical)

N•m/bar[lb•in/1000 psi]

0.8 [488]

0.9
0.96 [590][549]0.007
8 [0.00575]

1.08 [610]

Mass moment of inertia of rotating
components

kg•m2[slug•ft2]

0.0077[0.00568]

0.0078[0.00575

0.0143[0.01055]

0.0143[0.01052]

Mass (weight dry, without charge
pump or auxiliary flange)

kg [lb]65 [143]

65 [143]

96.2 [212]96.2 [212]

Oil volume

l [US gal]

2.3 [0.61]

2.3 [0.61]

4.2 [1.1]

4.2 [1.1]* Applies for each rotating group.

Physical properties

28 | © Danfoss | December 2021

Description

045/053060/068

Mounting flange per ISO 3019-1

Flange 101-2 (SAE B), special bolt

Flange 127-4 (SAE C)

Input shaft outer diameter, splines
per ISO 3019-1• Ø25 mm - 4 (SAE B-B, 15 teeth)• Ø32 mm - 4 (SAE-C, 14 teeth)• Ø31 mm - 4 (19 teeth)• Ø32 mm - 4 (SAE C, 14 teeth)• Ø35 mm - 4 (SAE C, 21 teeth)

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H1T 045/053, 060/068 Axial Piston Tandem Pumps
Technical Specifications
Physical properties (continued)
Description

045/053060/068

Auxiliary mounting flange with
Flange 82–2 outer dia:
metric fasteners, shaft outer diameter • Ø16 mm - 4 (SAE A, 9 teeth)and splines per ISO 3019-1• Ø19 mm - 4 (SAE A, 11 teeth)
Flange 101–2 outer dia:• Ø22 mm - 4 (SAE B, 13 teeth)• Ø25 mm - 4 (SAE B-B, 15 teeth)

Flange 101–2 outer dia:• Ø22 mm - 4 (SAE B, 13 teeth)• Ø25 mm - 4 (SAE B-B, 15 teeth)

Charge inlet port per ISO 11926-1

7∕ -14 (SAE O-ring boss)
8

1 1∕16 -14 (SAE O-ring boss)

Main port configuration

ISO 11926-1: 1 5∕16 -12 (SAE O-ringboss)

ISO 6162: M12 x 1.75 (Split flange)

Other ports

SAE O-ring boss

Customer interface threads

Metric fasteners

Operating parameters for H1 Tandem Pumps
Input Speed (at minimum charge/control pressure)Description

Size 045/053

Size 060/068

Minimum for external charge supply1)

500 min-1 (rpm)

500 min-1 (rpm)Rated

3400 min-1 (rpm)3500 min-1 (rpm)Maximum

3500 min-1 (rpm)4000 min-1 (rpm)1) Full performance (pressure and displacement) possible at minimum charge and control pressure supply.

System pressure
Description
System pressure

Control pressure

Size 045

Size 053

Size 060

Size 068

Max. working

420 bar [6092 psi] 380 bar [5511 psi] 420 bar [6090 psi] 380 bar [5510 psi]

Maximum (peak)

450 bar [6527 psi] 400 bar [5802 psi] 450 bar [6525 psi] 400 bar [5800 psi]

Max. low loop

45 bar [653 psi]

45 bar [650 psi]

Min. low loop

10 bar [145 psi]

10 bar [145 psi]

Min. at corner
power (EDC,
MDC, FNR)

21.5 bar [312 psi]

18.5 bar [270 psi]

Maximum

40 bar [580 psi]

40 bar [580 psi]

Other pressure type for all tandem pumps
Description
Charge pressure

Case pressure
Lip seal external© Danfoss | December 2021

045–068
Minimum without CCO valve

14.5 bar [210 psi]

Minimum with CCO valve

18 bar [265 psi]

Maximum

34 bar [493 psi]

Rated

3.0 bar [44.0 psi]

Maximum

5.0 bar [73.0 psi]

Maximum

0.4 bar [5.8 psi]

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H1T 045/053, 060/068 Axial Piston Tandem Pumps
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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H1T 045/053, 060/068 Axial Piston Tandem Pumps
Pressure Measurements
Port locations and gauge installation - 045/053
The following table and drawings show the port locations and gauge sizes needed. When testing systempressures, calibrate pressure gauges frequently to ensure accuracy. Use snubbers to protect gauges.
Port information
Port identifier

Port size

Wrench size

Reading

Gauge size, bar [psi]L1, L2, L3

1 1/16-12 UNF 2B

MA, MB, MC, MD

9/16-18 UNF

9/16 internal hex

Case drain

10 bar [100 psi]

1/4 internal hex

System pressure

600 bar [10,000 psi]

M3

9/16-18 UNF 2B

1/4 internal hex

Charge pressure

50 bar [1000 psi]

M4, M5
AM3

7/16-20 UNF 2B

3/16 internal hex

Servo pressure

50 bar [1000 psi]

9/16-18 UNF 2B

1/4 internal hex

Alternate Charge pressure

50 bar [1000 psi]

A, B, C, D

1 5/16-12-

System ports-

E

7/8-14-Charge filtration-

M14

7/16-20

1/4 internal hex

Case gauge port

10 bar [100 psi]

Port locations

M4

M5

M4

E

M5

L3

L1

C

B
D

A

MD

L2

MB

MA

M14

AM3

M3

MC

M3

M14

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H1T 045/053, 060/068 Axial Piston Tandem Pumps
Pressure Measurements
Port locations and gauge installation - 060/068
Port information
Port identifier

Port size

Wrench size

Reading

Gauge size, bar [psi]L1, L2, L3

1 1/16-12 UNF 2B

9/16 internal hex

Case drain

10 bar [100 psi]

MA, MB, MC, MD

9/16-18 UNF

1/4 internal hex

System pressure

600 bar [10,000 psi]

M3, AM3

9/16-18 UNF 2B

1/4 internal hex

Charge pressure

50 bar [1000 psi]

M4, M5

7/16-20 UNF 2B

3/16 internal hex

Servo pressure

50 bar [1000 psi]

M14

7/16-20

3/16 internal hex

Case gauge port

10 bar [100 psi]

A, B, C, D

1 5/16-12-

System ports-

E

7/8-14-Charge filtration-

Port locations
AM3
M3

M4

M5

L1

M4

M5

L1
L3

C
L2

D

E

B

A

MB

MA
M14

M14

MC

MD

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H1T 045/053, 060/068 Axial Piston Tandem Pumps
Initial Startup ProceduresStart-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.
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.
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Initial Startup Procedures
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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Service Manual
H1T 045/053, 060/068 Axial Piston Tandem Pumps
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.
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.
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.
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.
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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H1T 045/053, 060/068 Axial Piston Tandem Pumps
Troubleshooting
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
Erratic or no machinefunction

External controller malfunction or hydraulic systemproblem.

• Verify external controller problem using spare controller.
• Replace controller.
• Check hydraulic system fluid level/pressures/filters/etc.
• Fix hydraulic system problems.

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

Description

ActionFilter bypass activatedFilter is plugged causing fluid to bypass filter.

Replace filter. Check that bypass switch indicates proper
operation after filter is replaced.

Filter bypass indicator switch Filter bypass indicator switch is indicating wrong bypass
situation.

Check/replace filter switch.
• Open resistance ≥ 510 Ω• Closed resistance ≤ 122 Ω

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 51).
• If neutral is still impossible to set, balance the swashplate(see Mechanical Neutral Adjustment on page 53).
• 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.

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H1T 045/053, 060/068 Axial Piston Tandem Pumps
Troubleshooting
Item

Description

ActionExchange 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.

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 heat

System Operating Hot

exchanger

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.

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.

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H1T 045/053, 060/068 Axial Piston Tandem Pumps
Troubleshooting
Item

Description

ActionCharge 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.

System Noise or Vibration

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.

Sluggish System Response
Item

Description

ActionOil level in reservoir

Low oil level causes sluggish response.

Fill reservoir.

High pressure relief valves/pressure limiter settings

Incorrect pressure settings affects system reaction time.

Adjust or replace high pressure relief valves.

Low prime mover speed

Low engine speed reduces system performance.

Adjust engine speed.

Charge pressure

Incorrect pressure affects system performance.

Measure and adjust charge pressure relief or replace chargepump.

Air in system

Air in system produces sluggish system response.

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

Contaminated control
orifices

Control orifices are plugged.

Clean control orifices.

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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H1T 045/053, 060/068 Axial Piston Tandem Pumps
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 32 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.

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H1T 045/053, 060/068 Axial Piston Tandem Pumps
Adjustments
Charge Pressure Relief Valve Adjustment
Operate the system with the pump in neutral (zero displacement) when measuring charge pressures.

Old style

Old styleNew styleP109549

This procedure explains how to check and adjust the charge pressure relief valve.
Charge pressure adjustment

045/053060/068

M3
M3

1
2
1

L2

L2
2

P109550

Lock nut, wrench size 19 mm, torque 40 N•m [29.5 lb•ft] (pos. 1)
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Service Manual
H1T 045/053, 060/068 Axial Piston Tandem Pumps
Adjustments
Item

Port description

Wrench size

TorqueGauge size

M3

Charge pressure gauge¼ in

24 N•m [17 lb•ft]

0–50 bar[0–1000 psi]

L2

Case drain

9/16 in (045/053)

48.5 N•m [35.8 lb•ft] (045/053)

5/8 in (060/068)

148 N•m [109 lb•ft] (060/068)

0–10 bar[0–100 psi]

See Fastener Size and Torque Chart on page 77 for torques and wrench sizes on other charge pressure
relief valves.
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 pressure port L1, L2, or L3.
The table below shows the acceptable pump charge pressure range for some nominal charge relief
valve settings (refer to model code located on serial number plate).
Charge pressure range setting
Current
code

20

22

24

26

28

30

32

34

NA

Old code

BK

BB

BD

BF

BH

CK

CB

NA

CD

Pressuresetting

20 ± 1.5 bar[290 ± 21.8
psi]

22 ± 1.5 bar[319 ± 21.8psi]

24 ± 1.5 bar[348 ± 21.8
psi]

26 ± 1.5 bar[377 ± 21.8
psi]

28 ± 1.5 bar[406 ± 21.8
psi]

30 ± 1.5 bar[435 ± 21.8
psi]

32 ± 1.5 bar[464 ± 21.8
psi]

34 ± 1.5 bar[493 ± 21.8psi]

36 ± 1.5 bar[522 ± 21.8
psi]

Listed pressures assume a pump speed of 1800 min-1 (rpm), a reservoir temperature of 50°C [120°F],
and charge flow of 30 l/min [7.9 US gal/min]; referenced to case pressure. At higher pump speeds or
higher charge flows the charge pressure will rise over the rated setting.
3. Loosen the locknut and rotate the adjusting screw clockwise to increase the setting; orcounterclockwise to decrease it.
4. Subtract the case pressure reading to compute the actual charge pressure.
Pressure change per turn is dependent on charge flow entering pump.
5. While holding the adjusting screw, torque locknut to 40 N•m [30 lbf•ft].
6. When you achieve the desired charge pressure setting, remove the gauges and plug the ports.

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H1T 045/053, 060/068 Axial Piston Tandem Pumps
Adjustments
Charge check / HPRV adjustment
The charge check/HPRV combines the charge check and high pressure relief functions. Whenever you
replace a charge check/HPRV, operate the vehicle/machine through its full range of functions to ensure
proper pump operation. The charge check/HPRVs are preset at the factory, no adjustment is possible.
Checking for proper charge check / HPRV operation
If you suspect charge check/HPRV malfunction, swap valves and test operation. If the symptoms switch
direction, replace the faulty valve.

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Service Manual
H1T 045/053, 060/068 Axial Piston Tandem Pumps
Adjustments
Pressure Limiter
Pressure Limiter Screens

W Warning
Pumps with only HPRV valves no longer contain pressure limiter (PL) screens and retainer. To convert thepumps to use pressure limiter valves, please contact your Danfoss Service Partner. Pumps that have PL
valves without PL screens and retainers are at high risk of contamination and product malfunction.
H1P Base Models with pressure settings option B include PL screens and retainers.
Pressure Limiter Adjustment (060/068 only)
Lock motor output shaft to adjust the pressure limiter setting. Lock the vehicle’s brakes or rigidly fix thework function so it cannot rotate.
Ensure charge pressure is properly set before checking pressure limiter.
Pressure limiter adjustment

060/068(4x) 2(4x) 1(2x) 3

AM3
MB

MC

L2
M3
3

(2x)

MA
MD

P109551

LegendItem

Description

Wrench size

TorqueGauge size

1

Lock nut

14 mm

20 N•m [15 lb•ft]-

2

Adjusting screw

6 mm

-

-

3

HPRV Valve

22 mm

70 N•m [52 lb•ft]-

M3, AM3

Charge pressuregauge port

¼ inch43 N•m [32 lb•ft]

0 - 50 bar [0 - 1000
psi]

L2

Case drain port

5/8 inch

148 N•m [109 lb•ft]

0 - 10 bar [0 - 100 psi]

MA, MB, MC, MD

System pressuregauge ports¼ inch43 N•m [32 lb•ft]

0 - 600 bar [0 - 10,000
psi]

Endcaps are different for clockwise and counter clockwise rotation.
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H1T 045/053, 060/068 Axial Piston Tandem Pumps
Adjustments
PL valve adjustment Clockwise

PL valve adjustment Counterclockwise

060/0681

060/068

2

4

2

1

Clockwiserotation

Counterclockwise
rotation

4

3

3

C

C

D

D

B

B

A

A

P109552

Legend:Controls pressure ports: B = 1, A = 2, C = 3, D = 4
Lock nut torque = 20 Nm [15 lb•ft]

P109553

Legend:Controls pressure ports: A = 1, B = 2, D = 3, C = 4
Lock nut torque = 20 Nm [15 lb•ft]

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)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

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 17 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 an internal hex wrench.
Wrench size is in the diagram on the previous page.
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.
8. Repeat steps 4. and 5. until you reach the desired PL setting.
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H1T 045/053, 060/068 Axial Piston Tandem Pumps
Adjustments
9. After adjustment, torque the locknut (L024) to 12 N•m [9 lbf•ft].

C Caution
Do not over torque.
10. Shut down the prime mover.
11. Remove gauges and replace plugs.

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H1T 045/053, 060/068 Axial Piston Tandem Pumps
Adjustments
Charge check / HPRV adjustment
The charge check/HPRV combines the charge check and high pressure relief functions. Whenever you
replace a charge check/HPRV, operate the vehicle/machine through its full range of functions to ensure
proper pump operation. The charge check/HPRVs are preset at the factory, no adjustment is possible.
Checking for proper charge check / HPRV operation
If you suspect charge check/HPRV malfunction, swap valves and test operation. If the symptoms switch
direction, replace the faulty valve.

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Service Manual
H1T 045/053, 060/068 Axial Piston Tandem Pumps
Adjustments
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 (frame size 060/068 only to allow moving the vehicle/machine
short distances when you cannot start the prime mover.
Engaging the Bypass Function

060/068
B

A

P109554

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]

060—068

22 mm

70 N•m [52 lbf•ft]

115—280

30 mm

110 N•m [81 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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H1T 045/053, 060/068 Axial Piston Tandem Pumps
Adjustments
Displacement Limiter Adjustment for Tandem Pumps
An optional displacement limiter is located on each side of the pump housing. The maximum
displacement can be limited in either direction.
Displacement limiters are not pre-set by the factory but are installed to minimize the extension of theadjustment screw while not limiting the maximum displacement of the pump. A small amount ofclockwise screw adjustment is required before the 100% displacement condition is reached.

C Caution
Before adjusting the displacement limiter, mark the position of the servo cylinder.
Displacement limiter adjustment

E450
4 mm
E550
13 mm
23 N•m[17 lbf•ft]

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Service Manual
H1T 045/053, 060/068 Axial Piston Tandem Pumps
Adjustments
1. Loosen the locknut (E550).
Lock nut wrench size is 13 mm and torque is 23 N•m [17 lbf•ft] (for all tandem pumps).
2. Rotate the adjusting screw (E450).
Adjusting screw wrench size is 4 mm. Rotating the adjusting screw clockwise decreases the maximum
displacement of the pump while rotating the adjusting screw counterclockwise increases the
maximum displacement.
3. After establishing the desired maximum displacement setting, hold adjusting screw in place andtighten the locknut.
Refer to the table for change per turn. Clockwise rotation decreases displacement, counterclockwise
rotation increases it. Adjustment is possible from zero to maximum.

C Caution
Be sure servo cylinder does not rotate when displacement limiter locknut (E550) is torqued.
Approximate displacement change per revolution of adjusting screw

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Unit

045

053

060

068

cm3 [in3]

5.1 [0.311]

6.0 [0.366]

5.9 [0.360]

6.6 [0.403]

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Service Manual
H1T 045/053, 060/068 Axial Piston Tandem 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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H1T 045/053, 060/068 Axial Piston Tandem 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]12 N•m [9 lbf•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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H1T 045/053, 060/068 Axial Piston Tandem Pumps
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 or MC and MD
Pressure differential between M4 and M5 (optional)
Pressure differential between A and B or MC and MD (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.
Pump setup
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 for front pump, MC and
MD for rear pump).
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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H1T 045/053, 060/068 Axial Piston Tandem Pumps
Adjustments
Servo Adjustment for Tandem Pumps
Servo and system pressure gauge port locations (045/053)

AM3
X7

MB

MC

Control Cutoff (CCO)

M4

M5

1

E300
E350

AM3

MC

MB

B

C
D

A
MD
MA

M4

M5
P109257

Legend: Ports per ISO 11926–1

54 | © Danfoss | December 2021

A, B, C, D

System port: 1 5/16–12

MA, MB, MC, MD

System gauge port: 9/16–18

M3, AM3

Charge port: 9/16–18

M4, M5Servo gauge port: 7/16–20

X7

Brake gauge port: 9/16–18

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H1T 045/053, 060/068 Axial Piston Tandem Pumps
Adjustments
Servo and system pressure gauge port locations (060/068)

AM3

M5

M4

M3

M4
M5

C

D

A

B

MA

AM3

MC

MB

MD
P109555

Legend: Ports per ISO 11926–1
A, B, C, D

System port: Split flange M12 x 1.5

MA, MB, MC, MD

System gauge port: 9/16–18

M3, AM3

Charge port: 9/16–18

M4, M5Servo gauge port: 7/16–20

X7

Brake gauge port: 3/4–16

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.

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Adjustments
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 thePlug Size and Torque Chart on page 78.

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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.
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)

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Minor repair
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).
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 sequence1

2

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6

5

4

3

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Minor repair
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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H1T 045/053, 060/068 Axial Piston Tandem Pumps
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]

3 mm internal hex

2.5 N•m [1.8 lbf•ft]

F00A, F00B

Servo orifice

F00P

Supply orifice

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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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 sequence12© Danfoss | December 2021

6

5

4

3

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H1T 045/053, 060/068 Axial Piston Tandem 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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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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H1T 045/053, 060/068 Axial Piston Tandem 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 51 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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Minor repair
Shaft, Seal and Bearing Repair
The input shaft, seal, and front bearing are serviceable without disassembling the entire pump. Orient thepump on the work surface so the shaft is pointing up.
Shaft assembly (45/53 shown)

Protective
sleeve

J100
J150
J200

J250
J260
J150

J275
J300

1. Remove the retaining ring (J300) from the housing to release the shaft/seal/bearing subassembly.
2. Pry on the lip of the seal carrier (J275) to remove it from the pump.
3. Remove the seal carrier.
4. Remove and discard O-ring (J260).
5. Press the seal (J250) out of the carrier and discard.
6. 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 bearing.
7. Remove the retaining ring (J200) using retaining ring pliers. Press the bearing off the shaft.
8. Inspect the shaft journals for wear, scratching, and pits.
9. Check the splines for fretting; replace if damaged.
10. Rotate the bearing, if it does not rotate smoothly, replace it.

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H1T 045/053, 060/068 Axial Piston Tandem Pumps
Minor repair
Shaft, Seal and Bearing Installation
1. Inspect the shaft journals for wear, scratching, and pits.
2. Check the splines for fretting; replace if damaged.
3. Rotate the bearing, if it does not rotate smoothly, replace it.
4. Press the bearing (J150) onto the shaft (J100) and replace the retaining ring (J200).
5. Ensure the retaining ring diameter is less than 38.84 mm [1.53 in] when installed on the shaft.
6. Install the shaft/bearing assembly into the pump.
7. Lubricate and install a new O-ring (J260) onto seal carrier (J275).
8. Press a new seal (J250) into the seal carrier.
Press the seal until it is flush within +0.12 mm [0.005 in] or -0.72 mm [0.003 in] of the inside lip of thecarrier:
Positioning seal in seal carrier
Press flush to this surface+0.12 mm [ 0.005 in] / -0.72 mm [ 0.028 in]
Seal
P106 498E

9. Cover the shaft with a protective sleeve while installing the seal carrier.
10. Hand press the seal carrier into the housing.
11. Ensure the seal carrier clears the retaining ring groove in the housing.
12. Remove the protective sleeve.
13. Install the retaining ring (J300).
14. Ensure the inside diameter of the retaining ring is greater then 68 mm [2.68 in] after installation.

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Minor repair
Charge Pump Repair (045/053 only)
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.
K351
K351

K975

K975

K351

K975

K301
K301

K250
K400 (x4)
A flange
K101

K250
K400 (x4)
B flange
K101 S300
S002

S001

S200

K205

S100
S500
K201
K205

K151
K350

K450
K350

K450

K300
K302

K150

Wrench size and torque
Item

K350

K351 (A flange)

K351 (B flange)

K400

Wrench size

10 mm internal hex

8 mm internal hex

18 mm

10 mm internal hex

Torque76 N•m [56 lbf•ft]

64 N•m [47 lbf•ft]

76 N•m [56 lbf•ft]

92 N•m [68 lbf•ft]

1. Remove screws (K351), and hangers (K975).
2. Remove running cover (K301).
3. Remove and discard seal ring (K250).
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Minor repair
4. Using a 10 mm internal hex, remove screws (K400), and cover (K101).
5. Remove and discard seal (S300).
6. Remove geroter cover (S200).
Note the position of the alignment pin (S500) in the housing. The alignment pin position is different
for clockwise or counterclockwise rotation.
7. Remove and disassemble charge pump assembly.
Charge pump components: shaft (K201), pin (S500), geroter (S100), two clips (K205).
8. Remove and discard gasket (K151). Remove alignment pins (K450).
9. If it is necessary to remove housing (K300), use a 10 mm internal hex to remove screws (K350).
10. Remove housing (K300).
11. Remove and discard seal (K150).
12. Inspect carefully all machined surfaces, geroter and cover, shaft, journal bearings in aux. pad andhousing.
If you find any nicks or scratches, any sign of worn or damage, replace the component (geroter kit or
shaft). Use a suitable press to remove and replace the journal bearings, see below:
Replacing the journal bearings

Gerotercover

Journalbearing

1.72 mm ± 0.3[0.07 inch ± 0.011

P107 999E

Charge Pump Installation
1. Lubricate and install new seal (K150).
2. Install housing (K300). Install screws (K350). Using a 10 mm internal hex, torque screws per listing intable.
3. Install alignment pins (K450). Install new gasket (K151).
4. Lubricate and reassemble the charge pump assembly, [shaft (K201), pin (S500), geroter (S100), twoclips (K205)].
Install the alignment pin (S500) in its original position. The alignment pin position is different for
clockwise or counterclockwise rotation.
5. Install the charge pump assembly into the housing.
6. Install the geroter cover (S200).
7. Lubricate and install the seal (S300).
8. Install the aux pad (K101).
9. Using a 10 mm internal hex, install screws (K400).
10. Lubricate and install seal (K250). Install running cover (K301).
11. Install screws (K351) and brackets (K975).
Torque screws per listing in the table, see Charge Pump Repair (045/053 only) on page 67.

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Minor repair
Charge Check and HPRV Repair (045/053)
The high pressure relief and charge check valve assemblies may be removed for cleaning andreplacement of the O-rings. These valves are factory set and are not field adjustable. Refer to the pumpmodel code for the factory setting when ordering replacements.
Charge check / HPRV

H003

R150 (4X)

H002
K010
K009
K008
K007
8 mm
80 N•m[59 lbf•ft]
R200 (4X)

Rear pump location shown. There are four valve assemblies in total.
1. Using an 8 mm internal hex wrench, remove the valve seat plugs (K007).
2. Carefully lift the valve (H002) and spring (H003) assemblies from the center section using a magnet.
3. Inspect the valves and mating seats in the valve seat plugs (K007) for damage or foreign material.
4. Lubricate and install new O-rings (K008, K010) and backup ring (K009) on valve seat plug (K007).
5. Verify that the conical springs (H003) are properly retained on the check relief valves (H002).
6. Install the valve assemblies into the center section.
Ensure each valve assembly moves freely in its bore.
7. Install the valve seat plugs into the center section and torque to 80 N•m [59 lbf•ft].
8. Operate the vehicle/machine through its full range of control to ensure proper operation. Check forleaks.

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H1T 045/053, 060/068 Axial Piston Tandem Pumps
Minor repair
HPRV Port Relationship
The illustration below illustrates the relationship between the HPRVs and the ports controlled by thosevalves.
HPRV port relationship

HPRV valve
Controls port B
HPRV valve
Controls port A
HPRV valve
Controls port D
HPRV valve
Controls port C

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Minor repair
HPRV (60/68)
Pressure Limiter Screens

W Warning
Pumps with only HPRV valves no longer contain pressure limiter (PL) screens and retainer. To convert thepumps to use pressure limiter valves, please contact your Danfoss Service Partner. Pumps that have PL
valves without PL screens and retainers are at high risk of contamination and product malfunction.
H1P Base Models with pressure settings option B include PL screens and retainers.
HPRV Repair (060/068)
The high pressure relief and charge check valve assemblies may be removed for cleaning andreplacement of the O-rings. These valves are factory set and are not field adjustable. Refer to the pumpmodel code for the factory setting when ordering replacements.
L300, L301,
L400, L401

For ports
C and D
QL401

L022

L024

QL400

For ports
A and B
L024

L022

QL301

L022

QL300

port B
L200

L068
L060
L100
port A

port C
L101

L060
L068

L201
port DP109251© Danfoss | December 2021

Item

Description

Wrench size

Torque

L300, L301, L400, L401

Pressure limiter plug assembly

14 mm

30 N•m [22 lbf•ft]

QL300, QL301, QL400, QL401

Pressure limiter valve assembly

17 mm

30 N•m [22 lbf•ft]

L100, L101, L200, L201

High Pressure Relief Valve

22 mm

70 N•m [51.6 lbf•ft]

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Minor repair
1. Mark the location of each valve prior to removal.
2. Using a 22 mm wrench remove the HPRVs.
3. Remove and discard the O-rings (L060) and backup rings (L068).
4. Clean oil off the sealing surfaces and inspect the sealing surfaces for nicks or scratches. Check thevalves for damage. Replace any damaged components.
5. Lubricate and install new backup rings (L068) and O-rings (L060).
6. Install HPRV and pressure limiter valves in their original locations.
7. Operate the vehicle/machine through its full range of control to ensure proper operation. Check forleaks.

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Minor repair
Charge Pressure Relief Valve Repair
Replace the charge pressure relief valve (V10-1 or V10-2) as a complete unit. Do not attempt to repair theinternal components of the valve.
See Charge Pressure Relief Valve Adjustment on page 41 for adjustment instructions.
Charge pressure relief valve

V10A

V10A

V10-3

V10-1

V10A
V10-2

P109568

Legend:V10-1, V10-3 wrench size: 27 mm, torque to 52 N•m [38 lbf•ft]
V10-2 wrench size: 1 inch, torque to 52 N•m [38 lbf•ft]
1. Using a 27 mm (V10-1) or a 1 in (V10-2) wrench, remove the charge pressure relief valve.
2. Discard the O-rings (V10A).
3. Inspect the sealing surfaces of the pump and charge pressure relief valve for nicks or scratches.
4. Replace components as necessary.
5. Lubricate and install new O-rings (V10A).
6. Install the charge pressure relief valve (V10). Torque to 52 N•m [38 lbf•ft].
7. Operate vehicle/machine through full range of controls to ensure proper operation.

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H1T 045/053, 060/068 Axial Piston Tandem Pumps
Minor repair
Control Cut-off Valve / Brake Valve Repair
Replace the control cut-off valve as a complete unit. Do not attempt to repair the internal components ofthe valve.
Control cutoff valve (045/053)

G10
G10A

G20

1 1/16in46 N•m[34 lbf•ft]
G30

24 mm
9 N•m
[7 lbf•ft]
E101 401E

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H1T 045/053, 060/068 Axial Piston Tandem Pumps
Minor repair
Control cutoff valve (060/068)
G20

G30

G10
G30
G10A

G20

G10A
G10

1. Disconnect the coil from the vehicle/machine wire harness.
2. Using a 24 mm hex wrench, remove the control cut-off valve coil nut (G30).
3. Remove the coil (G20).
4. Use a 1 1/16 in hex wrench to remove the control cut-off valve (G10).
5. Remove and discard the O-rings and backup rings (G10A).
6. Inspect the sealing surfaces of the pump and control valve for nicks or scratches.
7. Replace components as necessary.
8. Lubricate and install new O-rings (G10A) onto the valve.
9. Install the control valve (G10). Torque to 46 N•m [34 lbf•ft].
10. Slide the coil (G20) onto the valve.
11. Install the coil nut (G30). Torque to 9 N•m [7 lbf•ft].

C Caution
Do not over torque.
12. Operate vehicle/machine through full range of controls to ensure proper operation.

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H1T 045/053, 060/068 Axial Piston Tandem Pumps
Torque Chart
Fasteners and Plugs
D065
D250

G250

V10

A Pad
K350
G350
D015

B015

D060
D050

B020

G250
E350

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B Pad
K350

K007

G350

P109564

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Torque Chart

G250

B015

B015

G250

B015
B020

B015

B020

B020

B020

G250

G250

D065
D065
G250

G250

V10

P109558

Fastener Size and Torque Chart
Item

Fastener

Wrench size

Torque

D015

Neutral adjust screw

4 mm internal hex

NA

D050

Control coil mounting screw

4 mm internal hex

8 N•m [5.9 lbf•ft]

D060

Neutral adjust locking nut

13 mm hex

10 N•m [7 lbf•ft]

D200

Swash plate feedback pin (not shown)

13 mm hex

25 N•m [18.4 lbf•ft]

D250

Electric control mounting screw

5 mm internal hex

13 N•m [9.5 lbf•ft]

E350

Servo cylinder locking screw

10 mm hex

14.5 N•m [11 lbf•ft]

G10

Control cut-off valve

1 1/16 in hex

45 N•m [33 lbf•ft]

G10B

Control cut-off valve coil nut

24 mm hex

10 N•m [7.5 lbf•ft]

K007

Charge check / HPRV

8 mm internal hex

80 N•m [60 lbf•ft]

K350

A pad cover mounting screw

17 mm hex

64 N•m [47 lbf•ft]

B pad cover mounting screw

18 mm hex

76 N•m [56 lbf•ft]

L010

Pressure limiter adjust screw

L300/L400/L101/L201 Pressure limiter cartridge
L024

Pressure limiter locking nut

L100/L200/L101/L201 High pressure relief valve
V10-1
V10-2
V10-3

© Danfoss | December 2021

Charge relief valve

8 mm internal hex

NA

14 mm hex

30 N•m [22 lbf•ft]

14 mm hex

20 N•m [15 lbf•ft]

22 mm hex

70 N•m [52 lbf•ft]

27 mm hex

52 N•m [38 lbf•ft]

AX152886481761en-000501 | 77

Service Manual
H1T 045/053, 060/068 Axial Piston Tandem Pumps
Torque Chart
Item

Fastener

Wrench size

TorqueV020

Charge pressure adjusting screw

6 mm internal hex

NA

V022

Charge pressure locking nut

19 mm hex

40 N•m [30 lbf•ft]

Plug Size and Torque Chart
Item

78 | © Danfoss | December 2021

O-ring plug

Wrench size

TorqueB015

7/16 - 20

3/16 internal hex

20 N•m [15 lbf•ft]

B020 (45/53)

1-1/16 - 12

9/16 internal hex

48 N•m [35 lbf•ft]

B020 (60/68)

1-3/8 - 12

5/8 internal hex

148 N•m [109 lbf•ft]

D065

7/16 - 20

3/16 internal hex

12 N•m [9 lbf•ft]

G250

9/16 - 18

1/4 internal hex(hardened plug)

45 N•m [33 lbf•ft]

AX152886481761en-000501

Products we offer:

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Cartridge valves
DCV directional control
valvesElectric converters
Electric machines

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

Gear motors

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

Gear pumps

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

Hydraulic integrated
circuits (HICs)
Hydrostatic motors

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

Electric motors

Hydrostatic pumps
Orbital motors
PLUS+1® controllers
PLUS+1® displays
PLUS+1® joysticks andpedals
PLUS+1® operator
interfaces
PLUS+1® sensors
PLUS+1® software
PLUS+1® software services,support and training
Position controls andsensors
PVG proportional valves
Steering components andsystems
Telematics

Local address:

Hydro-Gear
www.hydro-gear.com
Daikin-Sauer-Danfoss
www.daikin-sauer-danfoss.com

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

Danfoss
Power Solutions GmbH & Co. OHG
Krokamp 35
D-24539 Neumünster, Germany
Phone: +49 4321 871 0

Danfoss
Power Solutions ApS
Nordborgvej 81
DK-6430 Nordborg, Denmark
Phone: +45 7488 2222

Danfoss
Power Solutions Trading(Shanghai) Co., Ltd.
Building #22, No. 1000 Jin Hai Rd
Jin Qiao, Pudong New District
Shanghai, China 201206
Phone: +86 21 2080 6201

Danfoss can accept no responsibility for possible errors in catalogues, brochures and other printed material. Danfoss reserves the right to alter its products without notice. This also applies to products
already on order provided that such alterations can be made without subsequent changes being necessary in specifications already agreed.
All trademarks in this material are property of the respective companies. Danfoss and the Danfoss logotype are trademarks of Danfoss A/S. All rights reserved.

© Danfoss | December 2021

AX152886481761en-000501