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Item

Description

Action

Oil filters

Clogged oil filters may result in an insufficient
supply of cool oil to the system.

Inspect the oil filters and verify that they are still
operable. Replace them if necessary.

Machine load

Excessive loads or extreme duty cycles can result in
the pump and/or motor operating at speeds and
pressures beyond system design limitations. 

Verify that the machine is operating within the
parameters for which it was designed. If necessary,
reduce the load on the machine.

System will not operate in one direction

Item

Description

Action

Input control signal (linkage, current, or
pressure)

A faulty control signal is being received at the
pump. (MDC - binding or broken linkage, EDC -
faulty or inadequate electrical signal, HDC -
blocked or incorrectly orificed control lines).

Verify that the input signal being received is
correct and identical in both directions. Adjust,
clean, repair, or replace the control module as
necessary.

Displacement limiters (if equipped)

The displacement limiters may be improperly
adjusted such that the servo piston is prevented
from moving in one direction.

Verify that the displacement limiters are adjusted
properly.

SCR (system check / relief) valves

The SCR valves are malfunctioning or improperly
set.

Verify that the SCR valves are operating properly.
Repair or replace them as necessary.

Pump control

A damaged or biased pump control may be
sending a signal commanding the pump to stroke
only in one direction.

Verify that the pump’s control is functioning
properly. Repair or replace it as necessary.

Servo pressure

The drain or supply path to one side of the servo
piston may be blocked.

Verify that the servo supply and drain paths are
unobstructed and that each orifice is of the correct
size and free of debris. Clean or repair them as
necessary.

System will not operate in either direction

Item

Description

Action

Oil level in reservoir

There is insufficient hydraulic fluid to supply the
system loop.

Fill the reservoir to the proper level with clean
hydraulic oil.

Displacement limiters

Displacement limiters may be improperly adjusted
such that the servo piston is locked in place.

Verify that the displacement limiters are adjusted
to the proper setting.

Input control signal
(linkage, current, or pressure)

A faulty control signal being received at the pump.
(MDC - binding or broken linkage, EDC - faulty or
inadequate electrical signal, HDC - blocked or
incorrectly orificed control lines)

Verify that the input signal being received is
correct and identical in both directions. Adjust,
clean, repair, or replace the input device as
necessary.

Oil filters

Clogged oil filters may result in an insufficient
supply of oil to the system.

Inspect the oil filters and verify that they are still
serviceable. Replace them as necessary.

Bypass valve

A partially activated bypass valve (one or both)
may result in a cross port leakage.

Verify that the bypass valves are closed and that
the valves are seating properly. Clean, repair, or
replace them as necessary.

Charge pressure
(in neutral)

Charge pressure may be insufficient to recharge
the system loop.

Inspect the charge pump for damage and verify
that the charge pressure relief valve is at the proper
setting. Repair or replace it as necessary.

Charge pressure
(in stroke)

There is low charge pressure resulting from internal
leakage within the system.

Repair or replace the component or components
within the system causing the internal leakage.

Servo pressure

There is an insufficient pressure differential across
the servo piston.

Check servo pressures to verify sufficient pressure
delta. Verify that the servo supply and drain paths
are unobstructed and that each orifice is of the
correct size and free of debris. Clean, repair, or
replace them as necessary.

Service Manual

Series 40 M46 Variable Pumps

Troubleshooting

 

©

 Danfoss | September 2017

11026743 | AX00000027en-US0202 | 15

Summary of Contents for Series 40 M46 Tandem

Page 1: ...Service Manual Series 40 M46 Variable Pumps powersolutions danfoss com...

Page 2: ...ayout add HC EDC Control BA October 2010 corrections to port location illustration AE March 2010 Fix Osaka address AD March 2009 added spool alignment illustration AC May 2008 Fixed the illustrations...

Page 3: ...operate in either direction 15 Neutral difficult or impossible to find 16 System response is sluggish 16 Electrical troubleshooting 17 Adjustments Standard procedures inspections and adjustments 18 W...

Page 4: ...cement control 36 Electronic displacement control hydraulic displacement control 37 MDC orifice repair 39 EDC HDC orifice repair 40 HC EDC Control Repair 41 Torque chart Fastener size and torque chart...

Page 5: ...eries 40 M46 variable displacement closed circuit pumps Remove the unit Prior to performing repairs remove the unit from the vehicle machine Chock the wheels on the vehicle or lock the mechanism to in...

Page 6: ...ponents 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 W Warning Protect yours...

Page 7: ...where the shaft exits the pump housing The spinning cylinder block contains seven reciprocating pistons A ball joint connects a brass slipper to each piston A spring washer and the force of charge pre...

Page 8: ...he angle of the pump swashplate determines which line is high pressure as well as the direction of fluid flow Case drain and heat exchanger The pump and motor require case drain lines to remove hot fl...

Page 9: ...le displacement pump Heat exchanger bypass Charge relief valve Displacement control valve Control handle Bypass valve Loop flushing module P106 608E Variable displacement motor Pump schematic Pump sch...

Page 10: ...gh temperatures and pressures accelerate 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 o...

Page 11: ...to disable the engine to prevent it 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 tim...

Page 12: ...se drain 10 150 MA MB 9 16 18 SAE 11 16 hex System pressure 600 9 000 M3 9 16 18 UNF 11 16 hex Charge pressure 50 750 M4 M5 9 16 18 SAE 11 16 hex Servo pressure 50 750 System valves Port identifier Re...

Page 13: ...ort locations P106 604E M4 M5 L1 L2 B A MA MB M3 RA RB R S BP Service Manual Series 40 M46 Variable Pumps Required tools and pressure measurements Danfoss September 2017 11026743 AX00000027en US0202 1...

Page 14: ...t idle speed Pump inlet vacuum High inlet vacuum causes noise cavitation Check that inlet line is not restricted and is the proper size Check filter and bypass valve Shaft couplings A loose shaft coup...

Page 15: ...r direction Item Description Action Oil level in reservoir There is insufficient hydraulic fluid to supply the system loop Fill the reservoir to the proper level with clean hydraulic oil Displacement...

Page 16: ...cription Action Reservoir oil level There is an insufficient amount of hydraulic fluid resulting in an inadequate supply for the system loop Fill the reservoir to the proper level with clean hydraulic...

Page 17: ...ctrical troubleshooting Item Description Action Control operates pump in one direction only Control coil had failed EDC Measure resistance at coil pins Resistance should be 14 20 ohms 24V or 3 66 ohms...

Page 18: ...a Danfoss Global Service Partner Pump adjustment This section offers instruction on adjustment of pump components Read through the entire topic before beginning a service activity Refer to Port locat...

Page 19: ...unction use a 5 8 in hex wrench to unthread the bypass valve Rotate the bypass valve approximately three turns counterclockwise Do not rotate more than 3 revolutions additional rotation permits extern...

Page 20: ...ossible Pressure code is marked on the valve Refer to the model code for pressure designation If you suspect SCR malfunction replace valve and test operation of pump This procedure explains how to rep...

Page 21: ...rench 3 Rotate the displacement limiter 911 to adjust maximum displacement Rotating the adjusting screw clockwise decreases the maximum displacement of the pump while rotating the adjusting screw coun...

Page 22: ...lock the wheels to prevent movement Measured data System pressure at MA System pressure at MB Pressure differential between MA and MB optional Pump Setup 1 Attach 600 bar 10 000 psi gauge to system pr...

Page 23: ...ed on a vehicle or test stand use the following procedure to adjust the pump displacement control to neutral position If pump is on a vehicle securely block the wheels to prevent movement Check swashp...

Page 24: ...pump is on a vehicle block the wheels to prevent movement Measured data Servo pressure at M4 Servo pressure at M5 Pressure differential between M4 and M5 optional Procedure 1 Attach 20 bar 300 psi gau...

Page 25: ...ntrol or coils See Minor repair for details W Warning Unintended movement of the machine or mechanism may cause injury to the technician or bystanders To protect against unintended movement secure the...

Page 26: ...screw counterclockwise until the pressure increases by an equal amount on the other gauge Again note the angular position of the wrench 5 Rotate the neutral adjusting screw clockwise half the distance...

Page 27: ...am P106 046E Maximum adjustment less than 120 Control spool Illustration shows how cam on adjusting pin rotates to adjust for neutral position after pump is re installed Service Manual Series 40 M46 V...

Page 28: ...me 2 Inspect the hydraulic fluid for signs of system contamination oil discoloration foam in the oil sludge or small metal particles Reassembly 1 Before replacing the pump on the machine replace all f...

Page 29: ...ng disassembly Use a 1 4 in hex wrench to hold neutral adjustment screw and a 9 16 in hex wrench to install hex nut 115 Torque to 37 N m 27 lbf ft Install sleeve 929 and snap ring 928 Displacement lim...

Page 30: ...is attached to the auxiliary pad remove the gear pump and O ring or gasket 1 Using a 9 16 in hex wrench remove screws 1506 and cover plate 1505 Remove and discard seal 1504 2 Using a 9 16 in hex wren...

Page 31: ...components Inspect pin 604 and key 605 for damage and replace parts if necessary Replace O ring 141 load ring 142 and seal 1504 whenever charge pump is disassembled Reassembly Charge pump parts are av...

Page 32: ...rst Orient the pump on the work surface so the shaft is pointing up with the charge pump 603 and key 605 removed from shaft See Charge pump on page 30 Removal 1 Using a snap ring pliers remove snap ri...

Page 33: ...ing installation Lubricate and press new seal 301 into pump cover 5 Install second snap ring 132 Remove installation sleeve Shaft seal installation tool P106 652E 7 in 2 75 in 0 370 in 0 750 in 3 in 2...

Page 34: ...Removal 1 Using a 1 inch hex wrench remove charge pressure relief plug 102 Remove and discard O ring 103 2 Remove shims 101 spring 104 and charge pressure relief valve 105 Inspection Inspect the seali...

Page 35: ...1002 Inspection Inspect the sealing surfaces of the pump for nicks or scratches Inspect the bypass valve 1001 sealing surface for nicks or scratches Replace any damaged parts Reassembly 1 Lubricate an...

Page 36: ...ve sleeve 1402 Remove and discard backup ring 1208 and O ring 302 Inspection Inspect all parts of control assembly Replace any damaged parts Inspect spool and sleeve for grooves scratches and other da...

Page 37: ...nual Displacement Control Neutral Return Bracket Adjustment on page 23 for adjustment procedure Manual displacement control P106 639E 1213 1 2 in 1210 3 8 in 302 1214 1216 1215 1208 1235 1207 303 1209...

Page 38: ...damaged or you suspect control malfunction replace entire control unit Inspect sleeve bore in housing for damage Reassembly 1 Lubricate and install O rings 1220 and 304 onto control housing 1201 or fo...

Page 39: ...ntrol 1229 O rings 1229 are supplied as part of control MDC orifice repair Removal 1 Using a 3 16 in internal hex wrench remove pipe plug 1219 2 Using a 1 8 in internal hex wrench remove filter or ori...

Page 40: ...d installation instructions 2 Using a 7 32 in internal hex wrench remove orifice plugs 1403 and 1404 Inspection Clean orifice Replace if necessary Reassembly 1 Using a 7 32 in internal hex wrench inst...

Page 41: ...hex wrench remove the six cap screws D250 2 Remove the control module and gasket D150 Discard the gasket 3 Inspect the machined surfaces on the control and top of the pump If you find any nicks or scr...

Page 42: ...n orientation Correct screen orientation 6 Install the control module and six cap screws D250 Remove plug on top of control to ensure the swashplate feedback pin is properly positioned in the center o...

Page 43: ...the cap screws D250 to 13 5 N m 10 lbf ft HC ECD Control P108776 D250 6X 5 mm D150 D200 D300 2X D084 Torque sequence 2 3 4 5 6 1 Service Manual Series 40 M46 Variable Pumps Minor repair Danfoss Septe...

Page 44: ...14 lbf ft 1213 Control handle nut 1 2 hex 15 N m 11 lbf ft 1210 Screw 3 8 14 N m 10 lbf ft Plug size and torque chart Item O ring plug Wrench size Torque 102 3 4 16 UNF 1 inch hex 108 N m 80 lbf ft 10...

Page 45: ...102 102 1001 158 806 3 places 1506 3 places 163 6 places 130 115 2 places 927 2 places 921 5 places 1210 920 5 places 107 2 places Front Rear Bottom Top Side Service Manual Series 40 M46 Variable Pump...

Page 46: ...Service Manual Series 40 M46 Variable Pumps 46 Danfoss September 2017 11026743 AX00000027en US0202...

Page 47: ...Service Manual Series 40 M46 Variable Pumps Danfoss September 2017 11026743 AX00000027en US0202 47...

Page 48: ...tions ApS Nordborgvej 81 DK 6430 Nordborg Denmark Phone 45 7488 2222 Danfoss Power Solutions US Company 2800 East 13th Street Ames IA 50010 USA Phone 1 515 239 6000 Danfoss Power Solutions Trading Sha...

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