Series 45 Frame G
Open Circuit Axial
Piston Pumps
Service Manual
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520L0605 • Rev AB • December 2010
Series 45 G Frame Open Circuit Axial Piston Pumps
Service Manual
Revisions
Table of Revisions
Date Page Changed Rev.
December 2010 last New Back Page AB
March 2003 - First revision -
HISTORY OF REVISIONS
© 2010 Sauer-Danfoss. All rights reserved.
Sauer-Danfoss accepts no responsibility for possible errors in catalogs, brochures and
other printed material. Sauer -Danfoss reserves the right to alter its products without
prior notice. This also applies to products already ordered, provided that such alterations
can be made without affecting agreed specications. All trademarks in this material
are properties of their respective owners. Sauer-Danfoss, the Sauer-Danfoss logotype,
the Sauer-Danfoss S-icon, PLUS+1™, What really matters is inside® and Know-How in
Motion™ are trademarks of the Sauer-Danfoss Group.
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520L0605 • Rev AB • December 2010
Series 45 G Frame Open Circuit Axial Piston Pumps
Service Manual
INTRODUCTION
TECHNICAL
SPECIFICATIONS
FEATURES
PRESSURE
MEASUREMENT
INITIAL START-UP
PROCEDURES
FLUID AND FILTER
MAINTENANCE
Overview ...........................................................................................................................................................5
Safety precautions ......................................................................................................................................... 5
Unintended machine movement ....................................................................................................... 5
Flammable cleaning solvents ...............................................................................................................5
Fluid under pressure ................................................................................................................................ 5
Personal safety ........................................................................................................................................... 5
Symbols used in Sauer-Danfoss literature .............................................................................................6
General description .......................................................................................................................................7
System circuit ...................................................................................................................................................8
General specications ..................................................................................................................................9
Type of mounting .....................................................................................................................................9
Auxiliary mounting pad options ......................................................................................................... 9
Control options ..........................................................................................................................................9
Port options ................................................................................................................................................9
Direction of rotation ................................................................................................................................9
Installation position ................................................................................................................................. 9
Technical specications ..........................................................................................................................9
General specications (continued) ........................................................................................................10
Hydraulic parameters ..................................................................................................................................10
Inlet pressure ............................................................................................................................................10
Pressure compensator valve setting ................................................................................................10
Case pressure ...........................................................................................................................................10
Hydraulic uid .........................................................................................................................................10
Hydraulic parameters (continued) .........................................................................................................11
Temperature range .................................................................................................................................11
Fluid viscosity ...........................................................................................................................................11
Filtration ....................................................................................................................................................11
Displacement limiter ...................................................................................................................................12
Auxiliary mounting pads ...........................................................................................................................12
Input shafts .....................................................................................................................................................12
Control options .............................................................................................................................................13
Operation ...................................................................................................................................................13
Control options .............................................................................................................................................14
Required tools ...............................................................................................................................................15
Port locations and gauge installation ...................................................................................................15
General .............................................................................................................................................................16
Start-up procedure ......................................................................................................................................16
Recommendations .......................................................................................................................................17
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520L0605 • Rev AB • December 2010
Series 45 G Frame Open Circuit Axial Piston Pumps
Service Manual
TROUBLESHOOTING
ADJUSTMENTS
MINOR REPAIR
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
PC control ........................................................................................................................................................21
LS control ........................................................................................................................................................22
Shaft seal replacement ...............................................................................................................................23
Removal ......................................................................................................................................................23
Installation .................................................................................................................................................23
Auxiliary pads ................................................................................................................................................24
Removal ......................................................................................................................................................24
Installation .................................................................................................................................................24
Control ..............................................................................................................................................................25
Disassembly ..............................................................................................................................................25
Inspection ..................................................................................................................................................25
Control (continued) .....................................................................................................................................26
Reassembly ...............................................................................................................................................26
Plug and tting sizes and torques ..........................................................................................................27
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520L0605 • Rev AB • December 2010
Series 45 G Frame Open Circuit Axial Piston Pumps
Service Manual
Introduction
This manual includes information for the installation, maintenance, and minor repair of
the Series 45 frame G 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 G
Frame axial piston pumps according to the procedures in this manual will not affect 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 Sauer-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. Sauer-Danfoss ASCs are trained by the factory and
certied on a regular basis. You can locate your nearest ASC using the distributor locator
at www.sauer-danfoss.com
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 sufcient 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.
OVERVIEW
SAFETY PRECAUTIONS
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520L0605 • Rev AB • December 2010
Series 45 G Frame Open Circuit Axial Piston Pumps
Service Manual
Introduction
SYMBOLS USED IN
SAUER-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 denes 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 specication
Parallelism specication
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 specication
Press in – press t
Pull out with tool – press t
Cover splines with installation
sleeve
Pressure measurement / gauge
location or specication
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520L0605 • Rev AB • December 2010
Series 45 G Frame Open Circuit Axial Piston Pumps
Service Manual
Introduction
Sauer-Danfoss Series 45 G 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. One half of the cylinder block is connected to pump inlet and the other
half to pump outlet, via the valve plate. 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
piston and spring. The servo piston opposes the action of the bias piston and 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 13.
GENERAL DESCRIPTION
Pump and control sectional view
LS adjustment
PC adjustment
LS spool
PC spool
LS control
(attached to endcap)
Displacement piston
Swashplate
Ta pered
roller
bearing
Shaft seal
Ta pered roller
bearing
Input shaft
Bias piston guide
Bias spring
Bias piston
Cylinder
block
Valve
plate
Cylinder
block
spring
Piston
Slipper
Slipper retainer
P104 002E
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520L0605 • Rev AB • December 2010
Series 45 G Frame Open Circuit Axial Piston Pumps
Service Manual
Introduction
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 demands1 while limiting the maximum pressure.
Therefore ow and pressure in the system are compensated to meet requirements.
1
Full available ow is a function of pump displacement, operating speed, and efciency. Refer to Series 45 Axial
Piston Open Circuit Pumps Technical Information, 520L0519 for details.
SYSTEM CIRCUIT
Pictorial circuit diagram
System pressure
Servo pressure
Actuator pressure
Load sense pressure
Actuator return
Suction / case drain /
system return
PVG 32
mulit-section
load
sensing
control
valve
P106 067E
Reservoir
Filter
Heat exchanger
Double-acting cylinder
Bi-directional
gear motor
GFrame Series 45
open circuit axial
piston pump with
load sensing control
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520L0605 • Rev AB • December 2010
Series 45 G Frame Open Circuit Axial Piston Pumps
Service Manual
Technical specications
Type of mounting
SAE-C mounting ange.
Auxiliary mounting pad options
SAE-A, SAE-B, SAE-B-B, SAE-C, SAE C-C
Control options
PC: Pressure Compensator
LS: Load Sensing (with PC)
Port options
Inlet and system ports: SAE anged ports, code 61 Inlet Code 62 outlet.
Axial (end) ports or radial (side) ports.
All other ports: SAE straight thread O-ring boss.
Direction of rotation
Clockwise or counterclockwise.
Installation position
Installation position is discretionary. To satisfy inlet pressure conditions, it is
recommended that the pump always be located below the lowest level of hydraulic uid
in the reservoir. The housing must always be lled with hydraulic uid.
Technical specifications
GENERAL
SPECIFICATIONS
Features and options
Model
Feature Unit G74B G90C
Maximum Displacement cm³ [in³] 74 [4.52] 90 [5.49]
Flow at rated speed (theoretical) l/min
[US gal/min]
177.6
[46.9]
198
[52.3]
Input torque at maximum displacement
(theoretical)
N•m/bar
[lbf•in/1000 psi]
1.178
[719]
1.432
[874]
Mass moment of inertia of internal
rotating components
kg•m²
[slug•ft²]
0.00630
[0.00465]
0.00650
[0.00480]
Weight Axial ports kg [lb] 29 [63]
Radial ports 36 [80]
Rotation Clockwise, Counterclockwise
Mounting SAE-C
Auxiliary mounting SAE-A, SAE-B, SAE-BB, SAE-C
System ports (type) 4-bolt split ange
System ports (location) Axial, Radial
Control types PC, Remote PC, LS, LS with internal bleed
Shafts Splined 14 tooth, 17 tooth
Straight Ø 31.75 mm [1.25 in]
Displacement limiters Optional, adjustable
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