Series 45

H Frame

Open Circuit

Axial Piston Pumps

Service Manual

2

520L0611 • Rev AB • March 2011

this material are properties of their respective owners. Sauer-Danfoss and the Sauer-Danfoss logotype are

trademarks of the Sauer-Danfoss Group.

Front cover illustrations: F101 348, F101 347, F101 345, P106 084

ORGANIZATION AND

HEADINGS

To help you quickly nd information in this manual, the material is divided into sections,

topics, subtopics, and details, with descriptive headings set in red type. Section titles

appear at the top of every page in large red type. Topic headings appear in the left hand

column in BOLD RED CAPITAL LETTERS. Subtopic headings appear in the body text in

bold red type and detail headings in italic red type.

References (example: See Topic xyz, page XX) to sections, headings, or other publications are

also formatted in red italic type. In Portable Document Format (PDF) les, these references

hyperlinks that jump to the corresponding document pages.

Dened terms and acronyms are set in bold black type in the text that denes or

introduces them. Thereafter, the terms and acronyms receive no special formatting.

Black italic type is used in the text to emphasize important information, or to set-off

words and terms used in an unconventional manner or alternative context. Red and blue

italics represent hyperlinked text in the PDF version of this document (see above).

An indented Table of Contents (TOC) appears on the next page. Tables and illustrations

in the TOC set in blue type. In the PDF version of this document, the TOC entries are

hyperlinked to the pages where they appear.

SPECIAL TEXT

FORMATTING

TABLE OF CONTENTS

INTRODUCTION

MEASUREMENT

INITIAL START-UP

PROCEDURES

FLUID AND FILTER

MAINTENANCE

Overview ...........................................................................................................................................................5

Safety precautions .........................................................................................................................................5

Symbols used in Sauer-Danfoss literature .............................................................................................6

General description ....................................................................................................................................... 7

General specications (continued) ........................................................................................................10

Hydraulic parameters ..................................................................................................................................10

Hydraulic parameters (continued) .........................................................................................................11

Input shafts .....................................................................................................................................................11

Port locations and gauge installation ...................................................................................................14

General .............................................................................................................................................................15

Start-up procedure ......................................................................................................................................15

Recommendations .......................................................................................................................................16

ADJUSTMENTS

MINOR REPAIR

Excessive noise and / or vibration ..........................................................................................................17

Actuator response is sluggish ..................................................................................................................17

System operating hot .................................................................................................................................18

Low pump output ow ..............................................................................................................................18

Pressure or ow instability ........................................................................................................................18

Pressure or ow instability (continued) ...............................................................................................19

PC second stage control ............................................................................................................................20

Shaft seal replacement ...............................................................................................................................23

Auxiliary pads ................................................................................................................................................24

Bias piston, servo piston, and optional displacement limiter .......................................................25

Pressure compensator valve ....................................................................................................................25

Pressure compensator valve (continued) ............................................................................................26

Load spring control .....................................................................................................................................26

TROUBLESHOOTING

This manual includes information for the installation, maintenance, and minor repair of

the Series 45 frame H 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 H

Frame axial piston pumps according to the procedures in this manual will not affect your

warranty.

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

A worldwide network of Sauer-Danfoss Authorized Service Centers (ASCs) is available

certied 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

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

Escaping hydraulic uid under pressure can have sufcient force to penetrate your skin

causing serious injury and/or infection. This uid may also be hot enough to cause burns.

Protect yourself from injury. Use proper safety equipment, including safety glasses, at all

times.

OVERVIEW

SAFETY PRECAUTIONS

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 denes the symbol and explains its purpose.

Sauer-Danfoss Series 45 H 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

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

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

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) are

available. For a detailed description of control operation, refer to Control options,

operation, page 13.

GENERAL DESCRIPTION

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

SAE-C mounting ange.

Auxiliary mounting pad options

SAE-A, SAE-B, SAE-B-B, SAE-C, SAE C-C

Control options

LS: Load Sensing (with PC)

Inlet and system ports: SAE anged ports, code 61 Inlet Code 62 outlet.

Axial (end) ports or radial (side) ports.

SPECIFICATIONS

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

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.

vehicle / machine manufacturer’s

recommendations or at these intervals:

EXCESSIVE NOISE AND /

OR VIBRATION

SLUGGISH

Insufcient hydraulic uid causes

cavitation.

Air in system causes noisy, erratic

control.

Check external system relief valve

setting.

Check input speed. Low input speeds decrease ow. Adjust input speed.

Check pump rotation.

Check for air in system.

REACHING PC SETTING

HIGH INLET VACUUM

damage internal pump

components.

INSTABILITY (continued)

Blocked LS signal line interferes

Chattering external relief valve

pump control.

System pressure will not rise above

PC setting.

External relief valve setting below

PC setting prevents pressure

poor operation.

Contamination may interfere with

movement of the PC spool.

Low temperature increases

viscosity. High uid viscosity

Too many ttings, bends, or long

piping causes high inlet vacuum.

High uid viscosity causes high

inlet vacuum.

PC SECOND STAGE

CONTROL

PC second stage setting is indicated in the pump model code. Refer to the Series 45 Open

Circuit Axial Piston Pumps Technical Information Manual 520L0519, for more information.

pressure in the system

before removing hoses,

ttings, gauges, or

components.

Unintended movement of

the machine or mechanism

may cause injury to the

To protect against

secure the machine or

disable / disconnect

servicing.

Failure to drain port X (spring cavity)

to reservoir may cause additional back

pressure on the PC spring, resulting in

pressure settings above the desired

specication. It is recommended that

this procedure be used on all Series 45,

57cc pumps, however it is particularly

hardware changes associated with the

PC cartridge.

2. Start the prime mover and run at

second stage adjustment screw,

damage internal

components and void the

manufacturer’s warranty.

Take precautions to ensure

system cleanliness when

removing and reinstalling

4. Shut down the prime mover. Disconnect the pilot hose installed at port X and

reinstall the plug.

3. While holding the position of the second stage adjustment screw, torque the seal

locknut to 23 N•m [17 lbf•ft].