Danfoss DDC20, Service Manual

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Introduction
Overview..............................................................................................................................................................................................4
Warranty.............................................................................................................................................................................................. 4
General instructions........................................................................................................................................................................ 4
Remove the unit.......................................................................................................................................................................... 4
Keep it clean..................................................................................................................................................................................4
Lubricate moving parts.............................................................................................................................................................4
Replace all O-rings and gaskets............................................................................................................................................. 4
Secure the unit.............................................................................................................................................................................5
Safety Precautions............................................................................................................................................................................5
Unintended machine movement..........................................................................................................................................5
Flammable cleaning solvents.................................................................................................................................................5
Fluid under pressure.................................................................................................................................................................. 5
Personal safety............................................................................................................................................................................. 5
Gauge port locations and installation
Gauge port locations and sizes- with Aux pad...................................................................................................................... 6
Gauge port locations and sizes- with Gerotor....................................................................................................................... 7
Gauge port locations and sizes- with Implement pump....................................................................................................8
Adjustments
Pump adjustment.............................................................................................................................................................................9
Standard Procedures.......................................................................................................................................................................9
Charge pressure relief valve......................................................................................................................................................... 9
High pressure relief valve............................................................................................................................................................10
Loop flushing valve....................................................................................................................................................................... 11
Troubleshooting
Troubleshooting overview......................................................................................................................................................... 12
System operating hot...................................................................................................................................................................12
Transmission operating normally in one direction only..................................................................................................12
System noise or vibration........................................................................................................................................................... 12
System will not operate in either direction.......................................................................................................................... 12
Sluggish system response...........................................................................................................................................................13
Minor repair
Charge pump...................................................................................................................................................................................14
Implement pump...........................................................................................................................................................................16
Shaft and shaft seal....................................................................................................................................................................... 17
High pressure relief valve (HPRV).............................................................................................................................................21
Charge pressure relief valve (CPRV)........................................................................................................................................ 22
Loop flushing valve....................................................................................................................................................................... 23
Bypass valve.....................................................................................................................................................................................24
Optional coupling..........................................................................................................................................................................25
Torque charts
Charge pump fastener and torque chart.............................................................................................................................. 26
Implement pump fasteners and torque chart.....................................................................................................................26
Gerotor plugs and torque........................................................................................................................................................... 27
Auxiliary pad plug sizes and torque chart.............................................................................................................................28
Implement pump plug sizes and torque chart................................................................................................................... 29
Service Manual
DDC20/24 Axial Piston Pumps
Contents
© Danfoss | August 2019 L1120413 | AX00000135en-000401 | 3