Danfoss 45 J Series User manual

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MAKING MODERN LIVING POSSIBLE
Service Manual
Series 45 J Frame
Open Circuit Axial Piston Pumps

Service Manual Series 45 J Frame Open Circuit Axial Piston Pumps
520L0607 • Rev AI • Sep 20132
Front cover illustrations: F301320_S45-FRAME-J
Table of Revisions
Date Page Changed Rev.
September 2013 - Danfoss conversion AI
December 2012 9 Displacement limiter is available - change to max. pressure AH
October 2012 various add electric controls AG
November 2010 last new last page AF
February 2010 last Fix Osaka address AE
July 2009 20 Pressure change - PC adjustment specs AD
March 2007 21 typo in illustration - set screw torque is 7.5-10.8Nm
[5.5 -8 lbf•ft]
AB
May 2005 - First edition A
History of Revisions

Service Manual Series 45 J Frame Open Circuit Axial Piston Pumps
520L0607 • Rev AI • Sep 2013 3
Contents
Introduction
Technical Specications
Features
Pressure Measurement
Initial Start-up Procedures
Fluid and Filter Maintenance
Troubleshooting
Overview ...................................................................................................................................................................................... 5
Safety precautions.................................................................................................................................................................... 5
Unintended machine movement ................................................................................................................................. 5
Flammable cleaning solvents......................................................................................................................................... 5
Fluid under pressure.......................................................................................................................................................... 5
Personal safety..................................................................................................................................................................... 5
Symbols used in Danfoss literature.................................................................................................................................... 6
General description.................................................................................................................................................................. 7
System circuit ............................................................................................................................................................................. 8
General specications............................................................................................................................................................. 9
Hydraulic parameters............................................................................................................................................................ 10
Inlet pressure...................................................................................................................................................................... 10
Pressure compensator valve setting.......................................................................................................................... 10
Case pressure...................................................................................................................................................................... 10
Hydraulic uid ................................................................................................................................................................... 10
Fluid viscosity ..................................................................................................................................................................... 10
Filtration .............................................................................................................................................................................. 10
Auxiliary mounting pads...................................................................................................................................................... 11
Input shafts ............................................................................................................................................................................... 11
Control options........................................................................................................................................................................ 12
PC control............................................................................................................................................................................. 12
LS control ............................................................................................................................................................................. 13
Electric Proportional Controls...................................................................................................................................... 14
Electric On/O Controls.................................................................................................................................................. 14
Required tools.......................................................................................................................................................................... 15
Port locations and gauge installation ............................................................................................................................. 15
General........................................................................................................................................................................................ 16
Start-up procedure................................................................................................................................................................. 16
Recommendations ................................................................................................................................................................. 17
Excessive noise and/or vibration....................................................................................................................................... 18
Actuator response is sluggish ............................................................................................................................................ 18
System operating hot............................................................................................................................................................ 19
Low pump output ow......................................................................................................................................................... 19
Pressure or ow instability .................................................................................................................................................. 19
Pressure or ow instability (continued)..........................................................................................................................20
System pressure not reaching PC setting......................................................................................................................20
High inlet vacuum ..................................................................................................................................................................20

Service Manual Series 45 J Frame Open Circuit Axial Piston Pumps
520L0607 • Rev AI • Sep 20134
Contents (continued)
Adjustments
Minor repair
PC control................................................................................................................................................................................... 21
LS control ...................................................................................................................................................................................22
Shaft seal replacement .........................................................................................................................................................23
Auxiliary pads...........................................................................................................................................................................24
LS and PC Controls..................................................................................................................................................................25
LS and PC Controls (continued).........................................................................................................................................26
Electric Controls....................................................................................................................................................................... 27
Servo Control Orice..............................................................................................................................................................29
Plug and tting sizes and torques ....................................................................................................................................30

Service Manual Series 45 J Frame Open Circuit Axial Piston Pumps
520L0607 • Rev AI • Sep 2013 5
Always consider safety precautions before beginning a service procedure. Protect yourself and others
from injury. Take these general precautions whenever servicing a hydraulic system.
Unintended machine movement
Warning
Unintended movement of the machine or mechanism may cause injury to the technician or
bystanders. To protect against unintended movement, secure the machine or disable / disconnect
the mechanism while servicing.
Flammable cleaning solvents
Warning
Some cleaning solvents are ammable. To avoid possible re, do not use cleaning solvents in an area
where a source of ignition may be present.
Fluid under pressure
Warning
Escaping hydraulic uid under pressure can have sucient force to penetrate your skin causing
serious injury and/or infection. This uid may also be hot enough to cause burns. Use caution when
dealing with hydraulic uid under pressure. Relieve pressure in the system before removing hoses,
ttings, gauges, or components. Never use your hand or any other body part to check for leaks in a
pressurized line. Seek medical attention immediately if you are cut by hydraulic uid.
Personal safety
Warning
Protect yourself from injury. Use proper safety equipment, including safety glasses, at all times.
Introduction
Overview
Safety Precautions
This manual includes information for the installation, maintenance, and minor repair of the Series 45
frame J open circuit axial piston pumps. The manual includes a description of the units and their
individual components, troubleshooting information, and minor repair procedures. Performing
installation, maintenance, and minor repair of Series 45 J frame axial piston pumps according to the
procedures in this manual will not aect your warranty.
Performing minor repairs requires the unit to be removed from the vehicle/machine. Thoroughly
clean the unit before beginning maintenance, or repair activities. Since dirt and contamination are
the greatest enemies of any type of hydraulic equipment, follow cleanliness requirements strictly.
This is especially important when changing the system lter and when removing hoses or plumbing.
A worldwide network of Danfoss Authorized Service Centers (ASCs) is available for major repairs.
Major repairs require the removal of the unit’s endcap, which voids the warranty unless done by an
ASC. Danfoss ASCs are trained by the factory and certied on a regular basis. You can locate your
nearest ASC using the distributor locator at www.Danfoss.com

Service Manual Series 45 J Frame Open Circuit Axial Piston Pumps
520L0607 • Rev AI • Sep 20136
Introduction (continued)
Symbols used in Danfoss
Literature
These symbols are in the illustrations and text of this manual. They communicate helpful information
at the point where it is most useful to the reader.
In most instances, the appearance of the symbol itself denotes its meaning. The legend below denes
the symbol and explains its purpose.
WARNING may result in injury
CAUTION may result in damage to
product or property
Reusable part
Non-reusable part, use a new part
Non-removable item
Option – either part may exist
Superseded – parts are not
interchangeable
Measurement required
Flatness specication
Parallelism specication
External hex head
Internal hex head
 Torx head
O-ring boss port
Tip, helpful suggestion
Lubricate with hydraulic uid
Apply grease/petroleum jelly
Apply locking compound
Inspect for wear or damage
Clean area or part
Be careful not to scratch or damage
Note correct orientation
Mark orientation for reinstallation
Torque specication
Press in – press t
Pull out with tool – press t
Cover splines with installation sleeve
Pressure measurement/gauge
location or specication

Service Manual Series 45 J Frame Open Circuit Axial Piston Pumps
520L0607 • Rev AI • Sep 2013 7
Danfoss Series 45 J frame open circuit piston pumps convert input torque into hydraulic power.
Rotational force is transmitted through the input shaft to the cylinder block. The input shaft is
supported by tapered roller bearings at the front and rear of the pump and is splined into the cylinder
block . A lip-seal at the front end of the pump prevents leakage where the shaft exits the pump
housing. The spinning cylinder block contains nine reciprocating pistons. Each piston has a brass
slipper connected at one end by a ball joint. The slippers are held to the swashplate by the spring
retainer and block spring. The block spring also holds the cylinder block to the valve plate. The
reciprocating movement of the pistons occurs as the slippers slide against the inclined swashplate
during rotation. Via the valve plate, one half of the cylinder block is connected to pump inlet and the
other half to pump outlet. As each piston cycles in and out of its bore, uid is drawn from the inlet
and displaced to the outlet thereby imparting power into the system circuit. A small amount of uid is
allowed to “leak” from the cylinder block/valve plate and slipper/swashplate interfaces for lubrication
and cooling. Case drain ports are provided to return this uid to the reservoir.
The volume of uid displaced into the system circuit is controlled by the angle of the swashplate. The
swashplate is forced into an inclined position (into stroke) by the bias spring. The servo piston
opposes the action of the bias spring forcing the swashplate out of stroke when hydraulic pressure in
the control circuit rises above the spring force.
The pump control, by varying the pressure at the servo piston, controls the displacement of uid in
the system circuit. Controls designed for Pressure Compensation (PC) or Load Sensing (LS) are
available. For a detailed description of control operation, refer to Control options, operation, page 12.
Introduction (continued)
General Description
Pump and control sectional view
LS spoolLS adjustment
PC adjustment
PC spool
Servo piston
Bias spring
Input shaft
Tapered
roller
bearing
Tapered
roller
bearing
Block
spring
Piston Slipper
Swashplate
Slipper retainer
Shaft seal
LS control
(attached to endcap)
Cylinder block
Valve plate
P104 362

Service Manual Series 45 J Frame Open Circuit Axial Piston Pumps
520L0607 • Rev AI • Sep 20138
The pump receives uid directly from the reservoir through the inlet line. A screen placed in the inlet
protects the pump from large contaminants. The output of the pump is directed to a PVG-32
multi-section load sensing directional control valve which directs uid to the actuators in the system.
Fluid returning from the system is cooled by a heat exchanger and cleaned by a lter before returning
to the reservoir.
The speed of the actuators in the system depends on the volume of uid being provided by the
pump. The operating pressure varies depending on actuator load, but is limited to an adjustable
maximum setting by the PC section of the pump control and by a system relief valve integrated into
the side module of the PVG valve.
The position of the PVG valve sets the demand for ow in the system and communicates this to the
pump control by means of a hydraulic signal (load sense signal). The pump will provide as much ow
to the system as it demands1while limiting the maximum pressure. Therefore ow and pressure in the
system are compensated to meet requirements.
1Full available ow is a function of pump displacement, operating speed, and eciency. Refer to Series 45 Axial
Piston Open Circuit Pumps Technical Information, 520L0676 for details.
Introduction (continued)
System Circuit
Pictorial circuit diagram
P104 366E
System pressure
Servo pressure
Actuator pressure
Load sense pressure
Actuator return
Suction / case drain /
system return
Reservoir Filter
Double-acting cylinder
PVG 32
multi-section
load
sensing
control
valve
Bi-directional
gear motor
Heat exchanger
J Frame Series 45
open circuit axial
piston pump with
load sensing control

Service Manual Series 45 J Frame Open Circuit Axial Piston Pumps
520L0607 • Rev AI • Sep 2013 9
Technical Specications
General Specications Features and options Model
Feature Unit J45B J51B J60B J65C J75C
Maximum Displacement cm³ [in³] 45 [2.75]] 51 [3.11] 60 [3.66] 65 [3.97] 75 [4.58]
Flow at rated speed (theoretical) l/min
[US gal/min] 126.0 [33.3] 137.7 [36.4] 156.0 [41.2] 162.6 [42.9] 180 [47. 5]
Input torque at maximum
displacement (theoretical) N•m/bar [lbf•in/1000 psi] 0.716 [436.9] 0.811 [495.1] 0.956 [583.6] 1.035 [631.4] 1.193 [728.1]
Mass moment of inertia of
internal rotating components kg•m² [slug•ft²] 0.00455 [0.00336] 0.00455 [0.00336] 0.00455 [0.00336] 0.00433 [0.00319] 0.00433 [0.00319]
Weight Axial ports kg [lb] 23.13 [51]
Radial ports 26.65 [58.8]
Rotation Clockwise, Counterclockwise
Mounting 2 bolt SAE-B, 4 bolt SAE-C
Auxiliary mounting SAE-A, SAE-B, SAE-BB, SAE-C
System ports (type) SAE R-ring boss. 4-bolt split ange
System ports (location) Axial, Radial
Control types PC, Remote PC, LS, LS with internal bleed
Shafts Splined 13-tooth, 14-tooth, 15-tooth
Tapered Ø 31.75 mm [1.25 in], 1:8 taper
Straight Ø 31.75 mm [1.25 in]
Displacement limiters Available
Ratings Model
Rating Units J45B J51B J60B J65C J75C
Input speed¹
minimum
min-1 (rpm)
500 500 500 500 500
continuous 2800 2700 2600 2500 2400
maximum 3360 3240 3120 3000 2880
Working
pressure maximum bar [psi] 310 [4495] 310 [4495] 310 [4495] 260 [3770] 260 [3770]
External shaft
loads
External moment (Me)N•m [lbf•in] 226
[2000] 226 [2000] 226 [2000] 226 [2000] 226 [2000]
Thrust in (Tin), out (Tout) N [lbf] 2200
[495] 2200 [495] 2200 [495] 2200 [495] 2200 [495]
Bearing life
at 140 bar [2030 psi]
B10 hours
29 712 29 712 29 712 10 755 10 755
at 210 bar [3045 psi] 6834 6834 6834 2474 2474
at 260 bar [3770 psi] 3151 3151 3151 — —
at 310 bar [4495 psi] 1666 1666 1666 — —
Mounting ange
load moments
Vibratory
(continuous) N•m [lbf•in]
SAE-C: 1500 [14 000], SAE-B: 735 [6500]
Shock (max) SAE-C: 5600 [50 000], SAE-B: 2600 [23 000]
1. Continuous input speeds are valid at 1 bar absolute [0 in HG vac] inlet pressure. Maximum input speeds require changing
the inlet pressure or reducing pump displacement.

Service Manual Series 45 J Frame Open Circuit Axial Piston Pumps
520L0607 • Rev AI • Sep 201310
Inlet pressure
Minimum pressure, continuous = 0.8 bar absolute [6.7 inches Hg vac.]
(at reduced maximum pump speed)
Minimum pressure, cold start = 0.5 bar absolute [15.1 inches Hg vac.]
Pressure compensator valve setting
Minimum: 100 bar [1450 psi]
Maximum: 310 bar [3770 psi] (depending on displacement)
For more information, refer to Series 45 J Frame Axial Piston Open Circuit Pumps Technical Information,
520L0676.
1 Hydraulic uid viscosity must be maintained within the prescribed limits.
2As measured at the hottest point in the system, e.g. drain line.
Technical specications
Hydraulic Parameters
Viscosity limits
Rating mm2/s (cSt)
[SUS]
νcontinuous minimum 9 [58]
maximum 110 [500]
νintermittent
minimum 6.4 [47]
maximum
(cold start) 1000 [4700]
Filtration
Required cleanliness level: ISO 4406 Class 18/13 or better. Refer to Danfoss publications Fluids and
Filtration BLN-9887 or 520L0463 and Design Guidelines for Selecting and Maintaining the Required
Hydraulic Fluid Cleanliness 520L0465. See Fluid and filter maintenance, page 17 for recommended uid
and lter change intervals.
Case pressure
Maximum continuous: 0.5 bar [7 psi] Above inlet
Intermittent: 2 bar [29 psi] Cold start
Hydraulic uid
Refer to Danfoss publication Fluids and Filtration BLN-9887 or 520L0463. For information on
biodegradable uids refer to Biodegradable Hydraulic Fluids,520L0465. See Fluid and filter
maintenance, page 17 for recommended uid and lter change intervals.
Temperature range1
Intermittent (cold start): - 40° C [- 40° F]
Continuous: 82° C [180° F]
Maximum2: 104° C [220° F]
Fluid viscosity

Service Manual Series 45 J Frame Open Circuit Axial Piston Pumps
520L0607 • Rev AI • Sep 2013 11
Features
Auxiliary Mounting Pads
Input Shafts Series 45 J frame pumps are available with a variety of splined, straight keyed, and tapered end shafts.
For information on shafts refer to Series 45 J Frame Axial Piston Open Circuit Pumps Technical
Information, 520L0676.
Auxiliary mounting pads are available for all
radial ported Series 45 pumps. These pads are
typically used for mounting auxiliary hydraulic
pumps.
Since the auxiliary pad operates under case
pressure, an O-ring must be used to seal the
auxiliary pump mounting ange to the pad. The
drive coupling is lubricated by oil from the main
pump case. For details refer to Series 45 J Frame
Axial Piston Open Circuit Pumps Technical
Information, 520L0676.
Auxiliary pad options
P104 361

Service Manual Series 45 J Frame Open Circuit Axial Piston Pumps
520L0607 • Rev AI • Sep 201312
The Series 45 Frames J have three possible general control options, a Load Sensing (LS) control with
Pressure Compensator (PC), a PC only control, or an electric control.
Bias spring and servo piston set swashplate position
Cross-section pump
Operation
The bias spring (1) pushes against the servo
piston (2) which pulls the swashplate (3) to max
angle causing the pump to stroke. Internal
pressure on the servo piston acts against the bias
spring to reduce the swashplate angle causing
the pump to destroke. Swashplate angle
determines pump outlet ow. The pump control,
depending on conditions in the system circuit,
sets swashplate angle by metering system
pressure to the servo piston.
PC control
The PC control design maintains a constant
pressure in the hydraulic circuit as ow varies.
The PC control modulates pump ow accordingly
to maintain system pressure at the PC setting as
the PC adjusting plug (4) and spring (5) denes.
When system pressure, acting on the non-spring
end of the PC spool (6), overcomes the force of
the PC spring, the spool shifts porting system
pressure to the servo piston and the swashplate
angle decreases. When system pressure drops
below the PC setting, the PC spring shifts the
spool in the opposite direction connecting the
servo piston to pump case and the swashplate
angle increases. The swashplate is maintained at
whatever angle is required to keep system
pressure at the PC setting.
Features (continued)
Control Options
PC spool shifts to port system pressure to servo
piston
Cross-section PC control
P104 049
4
5
6
P104 360
1
23

Service Manual Series 45 J Frame Open Circuit Axial Piston Pumps
520L0607 • Rev AI • Sep 2013 13
Features (continued)
Control Options
(continued)
LS control
The LS control design matches pump ow with
system demand. The LS control senses the ow
demand of the system as a pressure drop across
the External Control Valve (ECV). As the ECV
opens and closes, the pressure delta across the
valve changes. When opening, the delta
decreases. When closing, the delta increases. The
LS control then increases or decreases pump
ow to the system until the pressure delta
becomes equal to the LS setting as dened by
the LS adjusting plug (7) and spring (8).
Load
pressure
Load sense
pressure
System
pressure
Tank
Return
pressure
P101 665E
Typical load-sensing control valve
Pressure drop across external control valve denes
system demand
The LS control consists of two spool valves that
connect the servo piston either to pump case or
system pressure. The PC spool (6) controls the
pressure-compensating function of the control
as previously described. The LS spool (9) controls
the load-sensing function. The PC spool has
priority over the LS spool.
Through internal porting, system pressure
(upstream of ECV) is applied to the non-spring
end of the LS spool, and through hydraulic line
connected at port X, LS pressure (downstream of
ECV) is applied to the spring end. This
arrangement allows the LS spool to act on the
delta between system pressure and LS pressure.
The LS spring sets the threshold of operation (LS
setting).
Because the swashplate is biased to maximum angle, the pump attempts to deliver full ow to the
hydraulic system. When the ow being delivered exceeds demand, the pressure delta across the ECV
is great enough to overcome spring force and shift the LS spool porting system pressure to the servo
piston. The pump de-strokes reducing ow until the delta across the ECV becomes equal to the LS
setting. When ow being delivered is less than demand, the delta across the ECV drops below the LS
setting and the LS spring shifts the spool connecting the servo piston to pump case. The pump
strokes increasing ow until the delta across the ECV becomes equal to the LS setting.
When the external control valve is placed in neutral, it connects the LS signal line to drain. With no LS
pressure acting on the non-spring end of the LS spool, the pump adjusts stroke to whatever position
necessary to maintain system pressure at the LS setting. The pump is now in standby mode.
Because of the series arrangement of the LS and PC spools, the PC spool will override the LS spool. If
at any time system pressure reaches the PC setting, the PC spool will shift blocking the passage that
connects the LS spool with the servo piston and porting system pressure to the servo piston causing
the pump to destroke.
LS spool shifts to port system pressure to servo
piston
Cross-section LS control
Spool
Spring
guide
Spring
LS adjusting
plug
LS spring
PC adjusting
plug
Plug
Plug
SpoolSpring
guide
Spring
(PC heavy)
P104 051

Service Manual Series 45 J Frame Open Circuit Axial Piston Pumps
520L0607 • Rev AI • Sep 201314


Electric Proportional Controls
PLUS+1 Compliance
All Series 45 Electric controls have met and
passed the Danfoss PLUS+1 compliance standard
testing, and as such, this Series 45 control is
PLUS+1 compliant. PLUS+1 compliance blocks
are available on the Danfoss website, within the
PLUS+1 Guide section.
Electric Proportional Control Principle
The Electric Proportional Control consists of a
proportional solenoid integrated into a Remote
Pressure Compensated control. This control
allows the pump to be operated at any pressure
limit between the Load Sense and Pressure
Compensation settings by varying the current
sent to the solenoid.


Electric On/O Controls
PLUS+1 Compliance
All Series 45 Electric controls have met and
passed the Danfoss PLUS+1 compliance standard
testing, and as such, this Series 45 control is
PLUS+1 compliant. PLUS+1 compliance blocks
are available on the Danfoss website, within the
PLUS+1 Guide section.
Electric On-O Control Principle
The Electric On/O Control consists of an On/O
solenoid integrated into a Remote Pressure
Compensated control. This control allows the
pump to be operated at either the Load Sense
pressure setting when “On”, or the Pressure
Compensation pressure setting when “O”.
Features (continued)
Control Options
(continued)

Service Manual Series 45 J Frame Open Circuit Axial Piston Pumps
520L0607 • Rev AI • Sep 2013 15
The service procedures described in this manual can be performed using common mechanic’s hand
tools. Special tools, if required are shown. Calibrate pressure gauges frequently to ensure accuracy.
Use snubbers to protect gauges.
The illustration below shows gauge port locations. Recommended pressure gauges and ttings are in
the table.
Gauge port locations
Pressure measurement
Required Tools
Port Locations and Gauge
Installation
Gauge and port information
Port Purpose Range of gauge Fitting
M1 System pressure 0-300 bar [0-5000 psi] 9/16 - 18 O-ring tting
L1, L2 Case drain port 0-10 bar [0-100 psi] 7/8 - 14 O-ring tting
XLS signal 0-300 bar [0-5000 psi] 7/16 - 20 O-ring tting
(tee into LS signal line)
x
M1 L1 L2
P104 364

Service Manual Series 45 J Frame Open Circuit Axial Piston Pumps
520L0607 • Rev AI • Sep 201316
Caution
Incorrect shaft alignment may
result in damage to drive
shaft, bearings, or seal which
can cause external oil leakage.
Install Start-up Procedures
General
Start-up Procedure
1. Connect the pump to the prime mover. Ensure that pump shaft is properly aligned with the shaft
of the prime mover. 
2. Fill the reservoir with recommended hydraulic uid. Always lter uid through a 10 micron lter
pouring into the reservoir. Never reuse hydraulic uid.
3. Fill the main pump housing with clean hydraulic uid. Pour ltered oil directly into the upper most
case drain port.
4. Fill the inlet line leading from the pump to the reservoir. Check the inlet line for properly tightened
ttings and be certain it is free of restrictions and air leaks.
5. To ensure the pump stays lled with oil, install the case drain line in the upper most case drain
port.
6. Install a gauge at port M1 to monitor system pressure during start up.
Follow recommendations in the vehicle/machine operator’s manual for prime mover start up
procedures.
7. While watching the pressure gauge installed at M1, jog the prime mover or run at the lowest
possible speed until system pressure builds to normal levels (minimum 11 bar [160 psi]). Once
system pressure is established, increase to full operating speed. If system pressure is not
maintained, shut down the prime mover, determine cause, and take corrective action. Refer to
Troubleshooting, page 18.
8. Operate the hydraulic system for at least fteen minutes under light load conditions.
9. Check and adjust control settings as necessary after installation. Refer to Adjustments, page 21.
10. Shut down the prime mover and remove the pressure gauge. Replace plug at port M1.
11. Check the uid level in the reservoir; add clean ltered uid if necessary.
12. The pump is now ready for operation.
Follow this procedure when starting-up a new Series 45 installation or when restarting an
installation in which the pump has been removed.
Warning
Unintended movement of the machine or mechanism may cause injury to the technician or
bystanders. To protect against unintended movement, secure the machine or disable / disconnect
the mechanism while servicing.
Prior to installing the pump, inspect for damage incurred during shipping. Make certain all system
components (reservoir, hoses, valves, ttings, heat exchanger, etc.) are clean prior to lling with
uid.

Service Manual Series 45 J Frame Open Circuit Axial Piston Pumps
520L0607 • Rev AI • Sep 2013 17
Change the uid and lter per the
vehicle/machine manufacturer’s
recommendations or at these intervals:
Change the uid more frequently if it becomes
contaminated with foreign matter (dirt, water,
grease, etc.) or if the uid is subjected to
temperature levels greater that the recommended maximum.
Dispose of used hydraulic uid properly. Never reuse hydraulic uid.
Change lters whenever the uid is changed or when the lter indicator shows that it is necessary to
change the lter. Replace all uid lost during lter change.
To ensure optimum life of Series 45 products, perform regular maintenance of the uid and lter.
Contaminated uid is the main cause of unit failure. Take care to maintain uid cleanliness when
servicing.
Check the reservoir daily for proper uid level, the presence of water, and rancid uid odor. Water in
the uid may be noted by a cloudy or milky appearance or free water in the bottom of the reservoir.
Rancid odor indicates the uid has been exposed to excessive heat. Change the uid immediately if
these conditions occur. Correct the problem immediately.
Fluid and Filter Maintenance
Recommendations
Fluid and filter change interval
Reservoir type Maximum change interval
Sealed 2000 hours
Breather 500 hours

Service Manual Series 45 J Frame Open Circuit Axial Piston Pumps
520L0607 • Rev AI • Sep 201318
Troubleshooting
Excessive Noise and/or
Vibration
Actuator Response is
Sluggish
Item Description Action
Check uid level in reservoir. Insucient hydraulic uid causes
cavitation. Fill the reservoir to proper level.
Check for air in system. Air in system causes noisy, erratic
control. Purge air and tighten ttings. Check inlet for leaks.
Check pump inlet pressure/vacuum. Improper inlet conditions cause erratic behavior and low output
ow.
Correct pump inlet pressure /
vacuum conditions. Refer to
Hydraulic parameters, page 10.
Inspect shaft couplings. A loose or incorrect shaft coupling causes excessive noise and/or
vibration.
Repair or replace coupling and
ensure that correct coupling is
used.
Check shaft alignment. Misaligned shafts create excessive
noise and/or vibration. Correct shaft misalignment.
Hydraulic uid viscosity above
acceptable limits.
Hydraulic uid viscosity above
acceptable limits or low uid
temperature will not allow the
pump to ll or control to operate
properly.
Allow system to warm up before
operating, or use uid with the
appropriate viscosity grade for
expected operating temperatures.
See Hydraulic Fluids and Lubricants
Technical Information Manual,
520L0463.
Item Description Action
Check external system relief valve
setting. Low external relief valve setting slows down system.
Adjust external relief valve setting
following manufacturer’s
recommendations. External relief
setting must be above PC setting to
operate properly.
Check PC and LS control setting. Low PC setting prevents the pump from achieving full stroke. Low LS
setting limits output ow.
Adjust PC and LS setting. Refer to
Adjustments, page 21
Check LS control signal pressures. Incorrect LS signal will not allow
pump to operate correctly. Inspect system to ensure that proper LS signal transmit to pump.
Internal system leaks. Worn internal parts don’t allow the
pump to operate properly. Refer to Authorized Service Center for required repair.
Hydraulic uid viscosity above
acceptable limits.
Hydraulic uid viscosity above
acceptable limits or low uid
temperature will not allow the
pump to ll or control to operate
properly.
Allow system to warm up before
operation or sue uid with the
appropriate viscosity grade for
expected operating temperatures.
See Hydraulic Fluids and Lubricants
Technical Information Manual,
520L0463.
Check external system valving. Malfunctioning valving may not
allow system to respond properly. Repair or replace system valving as required.
Check pump case pressure. High case pressure causes the
system to be sluggish. Correct case drain line restrictions.
Check pump inlet pressure/vacuum. High inlet vacuum causes low
output ow. Correct inlet pressure conditions.

Service Manual Series 45 J Frame Open Circuit Axial Piston Pumps
520L0607 • Rev AI • Sep 2013 19
Troubleshooting
(continued)
System Operating Hot
Low Pump Output Flow
Pressure or Flow Instability
Item Description Action
Check uid level in reservoir. Insucient volume of hydraulic uid will not meet cooling demands
of system.
Fill reservoir to proper level. Verify
proper size of reservoir.
Inspect heat exchanger. Check air
ow and input air temperature for
the heat exchanger.
Insucient air ow, high input air
temperature, or undersized heat
exchanges will not meet cooling
demands of the system.
Clean, repair, or replace heat
exchanger as required. Verify
proper size of heat exchanger.
Check external system relief valve
setting. Fluid passing through relief valve adds heat to system.
Adjust external system relief valve
setting following manufacturer’s
recommendations. External relief
valve setting must be above PC
setting for proper operation.
Check pump inlet pressure/vacuum. High inlet vacuum adds heat to
system. Correct inlet pressure/vacuum conditions.
Item Description Action
Check uid level in reservoir. Insucient hydraulic uid will limit output ow and cause internal
damage to pump. Fill the reservoir to proper level.
Hydraulic uid viscosity above
acceptable limits.
Fluid viscosity above acceptable
limits or low uid temperature will
not allow the pump to ll or control
to operate properly.
Allow system to warm up before
operating, or use uid with the
appropriate viscosity grade for
expected operating temperatures.
See Hydraulic Fluids and Lubricants
Technical Information Manual,
520L0463.
Check external system relief valve
setting. Eternal relief valve set below PC setting causes low output ow.
Adjust external relief valve
following manufacturer’s
recommendation. External relief
valve setting must be above PC
setting to operate properly.
Check PC and LS control setting. Low PC setting prevents the pump
from achieving full stroke. Adjust PC and LS setting. Refer to Adjustment, page 21.
Check pump inlet pressure/vacuum. High inlet vacuum causes low
output ow. Correct inlet pressure conditions.
Check input speed. Low input speeds decrease ow. Adjust input speed.
Check pump rotation. Incorrect rotational conguration
causes low ow. Use pump with appropriate rotational conguration.
Item Description Action
Check for air in system. Air in system causes erratic
operation.
Activate PC allowing system to
bleed air. Check inlet line for leaks
and eliminate source of air
ingression.
Check control spools. Sticking control spools cause erratic
operation. Inspect spools for free movement in bore. Clean or replace.

Service Manual Series 45 J Frame Open Circuit Axial Piston Pumps
520L0607 • Rev AI • Sep 201320
System Pressure not
Reaching PC Setting
High Inlet Vacuum
Caution
High inlet vacuum causes
cavitation which can damage
internal pump components.
Troubleshooting
(continued)
Pressure or Flow Instability
(continued)
Item Description Action
Check LS setting. Low LS setting may cause
instability. Adjust LS setting to proper level. See Adjustments, page 21.
Check LS signal line. Blocked LS signal line interferes
with proper LS operation. Remove blockage.
Check external relief valve and PC
setting.
Insucient pressure dierential
between PC setting and external
relief valve.
Adjust external relief valve or PC
control settings to appropriate
level. Relief valve setting must be
above PC setting to operate
properly.
Check external relief valve. Chattering external relief valve may cause unstable feedback to pump
control. Adjust or replace relief valve.
Item Description Action
Check PC control setting. System pressure will not rise above
PC setting. Adjust PC to appropriate setting. Refer to Adjustments, page 21.
Check external relief valve. External relief valve setting below PC setting presents pressure
compensation.
Adjust external relief valve
according to manufacturer’s
recommendations. External relief
valve must be set above PC setting
to operate properly.
Inspect PC control spring. Broken, damaged, or missing spring
will cause erratic operation. Replace the spring as required.
Inspect PC spool for wear. Wear of PC spool causes internal
leakage in the control. Replace the spool as required.
Inspect PC spool for proper
orientation. Improper orientation results in poor operation. Correct orientation of spool.
Check PC control for contamination. Contamination may interfere with
movement of the PC spool.
Clean PC control components, take
appropriate action to eliminate
contamination.
Item Description Action
Check uid temperature. Low temperature increases viscosity. High uid viscosity causes
high inlet vacuum.
Allow system to warm up before
operating.
Inspect inlet screen. Blocked or restricted inlet screen
causes high inlet vacuum. Clean screen/remove blockage.
Check inlet piping. Too many ttings, bends, or long
piping causes high inlet vacuum. Eliminate ttings to make path more direct.
Hydraulic uid viscosity above
acceptable limits. High uid viscosity causes high inlet vacuum.
Select uid with appropriate
viscosity for expected operating
temperature. See Hydraulic Fluids
and Lubricants Technical Information
Manual, 520L0463.