Danfoss Series 40 M46 Tandem Service Manual

Service Manual

Axial Piston Variable Pumps

Series 40 M46 Tandem

powersolutions.danfoss.com

Revision history Table of revisions

Date Changed Rev

September 2017 minor edit - Displacement limiter torque change 0202

November 2014 Danfoss layout BA

September 2010 New Back Page AD

March 2010 Fix Osaka address AC

March 2009 added spool alignment illustration AB

June 2008 First edition AA

Service Manual

Series 40 M46 Tandem Variable Pumps

2 | © Danfoss | September 2017 11029852 | AX00000030en-US0202

Introduction

Overview..............................................................................................................................................................................................4

Warranty.............................................................................................................................................................................................. 4

General instructions........................................................................................................................................................................ 4

Safety precautions............................................................................................................................................................................4

Symbols used in Danfoss literature............................................................................................................................................6

Design...................................................................................................................................................................................................6

The system circuit.............................................................................................................................................................................7

Pump schematic............................................................................................................................................................................... 9

Fluid and filter maintenance

Fluid and filter recommendations........................................................................................................................................... 10

Initial startup procedures

General ..............................................................................................................................................................................................11

Start-up procedure........................................................................................................................................................................11

Pressure measurements

Required tools.................................................................................................................................................................................13

Port locations and gauge installation.....................................................................................................................................13

Troubleshooting

Overview........................................................................................................................................................................................... 15

Safety precautions.........................................................................................................................................................................15

System noise or vibration........................................................................................................................................................... 15

System operating hot...................................................................................................................................................................15

System will not operate in one direction.............................................................................................................................. 16

System will not operate in either direction.......................................................................................................................... 16

Neutral difficult or impossible to find.....................................................................................................................................17

System response is sluggish...................................................................................................................................................... 17

Electrical troubleshooting.......................................................................................................................................................... 18

Adjustments

Standard procedures, inspections, and adjustments....................................................................................................... 19

Warranty............................................................................................................................................................................................19

Pump adjustment.......................................................................................................................................................................... 19

Charge pressure relief valve.......................................................................................................................................................19

Engaging the bypass function.................................................................................................................................................. 20

System check/relief (SCR) valves.............................................................................................................................................. 21

Displacement limiter adjustment............................................................................................................................................ 22

Displacement limiter adjustment data.................................................................................................................................. 23

Swashplate neutral adjustment................................................................................................................................................23

Manual Displacement Control Bracket Neutral Adjustment..........................................................................................24

Electronic Displacement Control/Hydraulic Displacement Control Neutral Adjustment...................................25

Minor repair

Standard procedures, removing the pump..........................................................................................................................27

Displacement limiter.....................................................................................................................................................................27

Pressure filtration adapter.......................................................................................................................................................... 28

Charge pump...................................................................................................................................................................................29

Shaft seal...........................................................................................................................................................................................31

SCR valves.........................................................................................................................................................................................32

Charge pressure relief valve.......................................................................................................................................................33

Bypass valve.....................................................................................................................................................................................34

Manual displacement control....................................................................................................................................................35

Electronic Displacement Control/Hydraulic Displacement Control............................................................................36

MDC orifice repair..........................................................................................................................................................................38

EDC/HDC orifice repair.................................................................................................................................................................39

Torque chart

Fastener size and torque chart..................................................................................................................................................41

Plug size and torque chart..........................................................................................................................................................41

Service Manual

Series 40 M46 Tandem Variable Pumps

Contents

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Overview

This manual includes information for the installation, maintenance, and minor repair of the Series 40 M46 tandem pump. It includes a description of the unit and its individual components, troubleshooting information, and minor repair procedures.

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 filter and when removing hoses or plumbing.

A worldwide network of Danfoss Global Service Partners is available for major repairs. Danfoss Global Service Partners are trained by the factory and certified on a regular basis. You can locate your nearest Global Service Partner using the distributor locator at www.sauer-danfoss.com.

Warranty

Performing installation, maintenance, and minor repairs according to the procedures in this manual will not affect your warranty. Major repairs requiring the removal of a unit’s rear cover or front flange voids the warranty unless done by a Danfoss Global Service Partner.

General instructions

Follow these general procedures when repairing Series 40 M46 tandem variable displacement closed circuit pumps.

Remove the unit

Prior to performing major repairs, 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.

Keep it clean

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 adequate.

As with any precision equipment, all parts must be kept free of foreign materials and chemicals. Protect all exposed sealing surfaces and open cavities from damage and foreign material. If left unattended, cover the pump with a protective layer of plastic.

Replace all O-rings and gaskets

Replace all O-rings, gaskets and seals. Lightly lubricate all O-rings with clean hydraulic fluid or petroleum jelly prior to assembly.

Safety precautions

Always consider safety precautions before beginning a service procedure. Protect yourself and others from injury. Take the following general precautions whenever servicing a hydraulic system.

Service Manual

Series 40 M46 Tandem Variable Pumps

Introduction

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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 flammable. To avoid possible fire, do not use cleaning solvents in an area where a source of ignition may be present.

Fluid under pressure

Warning

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. Use caution when dealing with hydraulic fluid under pressure. Relieve pressure in the system before removing hoses, fittings, 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 fluid.

Personal safety

Warning

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

Hazardous material

Warning

Hydraulic fluid contains hazardous material. Avoid prolonged contact with hydraulic fluid. Always dispose of used hydraulic fluid according to state, and federal environmental regulations.

Service Manual

Series 40 M46 Tandem Variable Pumps

Introduction

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Symbols used in Danfoss literature

WARNING may result in injury Tip, helpful suggestion

CAUTION may result in damage to product or property

Lubricate with hydraulic fluid

Reusable part Apply grease / petroleum jelly

Non-reusable part, use a new part Apply locking compound

Non-removable item Inspect for wear or damage

Option - either part may exist Clean area or part

Superseded - parts are not interchangeable Be careful not to scratch or damage

Measurement required Note correct orientation

Flatness specification Mark orientation for reinstallation

Parallelism specification Torque specification

External hex head Press in - press fit

Internal hex head Pull out with tool – press fit

Torx head Cover splines with installation sleeve

O-ring boss port Pressure measurement/gauge location or

specification

The symbols above appear in the illustrations and text of this manual. They are intended to 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 above defines each symbol and explains its purpose.

Design

Danfoss Series 40 M46 closed 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 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 seven reciprocating pistons. Each piston has a brass slipper connected at one end by a ball joint. The slippers are held to the swashplate by a spring washer and charge pressure. 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 low pressure and the other half to high pressure. As each piston cycles in and out of its bore, fluid is replenished by charge flow and displaced to the outlet thereby imparting hydraulic power into the system. A small amount of fluid is allowed to flow from the cylinder block/valve plate and slipper/swashplate interfaces for lubrication and cooling. Excess flow across the charge pressure relief also flows through the case and is used for cooling. Case drain ports return this fluid to the reservoir.

The volume of fluid displaced into the system is controlled by the angle of the swashplate. The swashplate is forced into an inclined position (into stroke) by the servo piston.

The pump control, by varying the pressure at the servo piston, controls the displacement of fluid in the system circuit.

Service Manual

Series 40 M46 Tandem Variable Pumps

Introduction

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Cross section view

Piston

Slipper

Valve plate

Ball bearing

Gerotor

Shaft

Journal bearing

Swashplate bearing pin

Servo piston

Cylinder block

Manual displacement Control

Ball bearing

Slipper

Piston

Valve plate

Journal bearing

Swashplate bearing pin

Servo piston

Swashplate

P106665

The system circuit

The basic closed circuit

The main ports of the pump are connected by hydraulic lines to the main ports of the motor. Fluid flows, in either direction, from the pump to the motor then back to the pump in this closed circuit. 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.

A tandem circuit contains two pumps and motors. Each pump and motor circuit is similar to the one shown.

Case drain and heat exchanger

The pump and motor case drain lines remove hot fluid from the system. The pump and motor should be drained from their top most drain port to ensure the case remains full of fluid. The motor case drain can be connected to the lower drain port on the pump housing and out the top most port or feed into the case drain line coming from the pump ahead of the heat exchanger. A heat exchanger, with a bypass valve, is required to cool the case drain fluid before it returns to the reservoir.

Service Manual

Series 40 M46 Tandem Variable Pumps

Introduction

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System circuit diagram

Input shaft

Suction flow

Servo pressure

High pressure

Case flow

Charge pressure

Output shaft

Cylinder block assembly

Filter

Charge

pump

Reservoir

Cylinder

block

assembly

Heat exchanger

Check valves w/ high pressure relief valve

Variable displacement pump

Heat exchanger bypass

Charge relief valve

Displacement control valve

Control handle

Bypass

valve

Loop flushing

module

P106608

Variable displacement motor

Service Manual

Series 40 M46 Tandem Variable Pumps

Introduction

8 | © Danfoss | September 2017 11029852 | AX00000030en-US0202

Pump schematic

B N A

P100 587E

Above schematic shows the function of a Series 40 M46 axial piston variable displacement pump.

Service Manual

eries 40 M46 Tandem Variable Pumps

Introduction

Danfoss | September 2017

11029852 | AX00000030en-US0202 | 9

Fluid and filter recommendations

To ensure optimum life, perform regular maintenance of the fluid and filter. Contaminated fluid is the main 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 the reservoir. Rancid odor indicates the fluid has been exposed to excessive heat. Change the fluid immediately if these conditions occur. Correct the problem immediately.

Inspect vehicle for leaks daily. Change the fluid and filter per the vehicle/machine manufacturer’s recommendations or at these

intervals: First fluid change recommended at 500 hours.

Caution

High 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 whenever the fluid is changed or when the filter indicator shows that it is necessary to change the filter. Replace all fluid lost during filter change.

Fluid and filter change interval

Reservoir type Max. oil change interval

Sealed 2000 hours Breather 500 hours

Hazardous material

Warning

Hydraulic fluid contains hazardous material. Avoid contact with hydraulic fluid. Always dispose of used hydraulic fluid according to state, and federal environmental regulations.

Service Manual

Series 40 M46 Tandem Variable Pumps

Fluid and filter maintenance

General

Follow this procedure when starting-up a new pump installation or when restarting an installation in which 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.

Warning

Prior to installing the pump, inspect for damage that may have occurred during shipping.

Start-up procedure

1. Ensure that the machine hydraulic oil and system components (reservoir, hoses, valves, fittings, and

heat 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. Install a 50 bar [1000 psi] gauge in the charge pressure gauge port M3.

4. Fill the housing by adding filtered oil in the upper case drain port.

5. Fill the reservoir with hydraulic fluid of the recommended type and viscosity. Use a 10-micron

reservoir filler filter. Ensure inlet line from reservoir to pump is filled.

6. Disconnect the pump from all control input signals.

7. Re-install plug or fitting removed in step 4.

After start-up the oil level in the reservoir may drop due to filling of the system components. Check the level in the reservoir to maintain a full oil level throughout the start-up.

Warning

Damage to hydraulic components may occur if the oil supply is not maintained.

8. Use a common method to disable the engine to prevent the engine from starting. Crank the starter

for several seconds. Do not to exceed the engine manufacturer’s recommendation. Wait 30 seconds and then crank the engine a second time as stated above. This operation helps remove air from the system lines. Refill the reservoir to recommended full oil level.

9. When charge pressure begins to appear, 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 the system. Check for leaks at all line connections and listen for cavitation. Check for proper fluid level in reservoir.

Caution

Air entrapment in oil under high pressure may damage hydraulic components.

Caution

Do not run at maximum pressure until system is free of air and fluid has been thoroughly filtered.

10. When adequate charge pressure is established (as shown in model code), increase engine speed to

normal operating rpm to further purge residual air from the system.

Service Manual

Series 40 M46 Tandem Variable Pumps

Initial startup procedures

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11. Shut off engine. Connect pump control signal. 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.

12. Continue to cycle between forward and reverse for at least five minutes to bleed all air and flush

system contaminants out of loop.

Normal charge pressure fluctuation may occur during forward and reverse operation.

13. Check that the reservoir is full. Remove charge pressure gauge. Re-install charge pressure plug. The

pump is now ready for operation.

Service Manual

Series 40 M46 Tandem Variable Pumps

Initial startup procedures

Required tools

The service procedures described in this manual can be performed using common mechanic’s hand tools. Special tools, if required, are shown. When testing system pressures, calibrate pressure gauges frequently to ensure accuracy. Use snubbers to protect gauges.

Port locations and gauge installation

The following tables and drawing show the port locations and gauge sizes needed.

Port information

Port identifier Port size Wrench size Pressure obtained Gauge size, bar [psi]

L1, L2, L3 1-1/16 12 SAE 9/16 internal hex Case drain 10 [100] MA, MB, MC, MD 9/16 18 SAE 11/16 hex System pressure 600 [10,000] M3 9/16 18 UNF 11/16 hex Charge pressure 50 [1000] M4, M5 9/16 18 SAE 11/16 hex Servo pressure 50 [1000]

System valves

Port identifier Relief Port size Wrench size

RA A port pressure relief valve 1-5/16 12 UNF 1-1/4 hex RB B port pressure relief valve 1-5/16 12 UNF 1-1/4 hex RC C port pressure relief valve 1-5/16 12 UNF 1-1/4 hex RD D port pressure relief valve 1-5/16 12 UNF 1-1/4 hex R Charge pressure relief valve 3/4 16 UNF 7/8 hex BP Bypass valve 5/8 18 UNF 1 inch hex

System ports

Port identifier Port size

A system pressure port 1-5/16 12 SAE B system pressure port 1-5/16 12 SAE C system pressure port 1-5/16 12 SAE D system pressure port 1-5/16 12 SAE S (charge pressure inlet) 1-5/16 12 SAE

Service Manual

Series 40 M46 Tandem Variable Pumps

Pressure measurements

Danfoss | September 2017 11029852 | AX00000030en-US0202 | 13

Port locations

P106663

Service Manual

Series 40 M46 Tandem Variable Pumps

Pressure measurements

+ 30 hidden pages

Danfoss Series 40 M46 Tandem Service Manual

Specifications and Main Features

Frequently Asked Questions

User Manual