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

Ordering replacement parts and service................................................................................................................................. 5

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

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

General instructions........................................................................................................................................................................ 7

Keep it clean..................................................................................................................................................................................7

Inspect for system contamination........................................................................................................................................ 7

Replace the O-rings and gaskets........................................................................................................................................... 7

Lubricate all moving parts....................................................................................................................................................... 7

Torque procedure....................................................................................................................................................................... 7

Variable displacement motors.....................................................................................................................................................7

Series 51-1 motors............................................................................................................................................................................8

Closed circuit......................................................................................................................................................................................9

Open circuit......................................................................................................................................................................................10

Shafts.................................................................................................................................................................................................. 11

Loop flushing...................................................................................................................................................................................12

Displacement limiters...................................................................................................................................................................13

Mounting configurations............................................................................................................................................................ 14

Speed sensors..................................................................................................................................................................................16

Controls............................................................................................................................................................................................. 17

Overview......................................................................................................................................................................................17

Two-position controls.................................................................................................................................................................. 17

Pressure-compensator controls................................................................................................................................................19

Proportional controls....................................................................................................................................................................20

General specifications.................................................................................................................................................................. 21

Technical data................................................................................................................................................................................. 21

Fluid specifications........................................................................................................................................................................22

Required tools................................................................................................................................................................................. 23

Port locations and gauge installation.....................................................................................................................................23

Fluid and filter recommendations........................................................................................................................................... 26

Hazardous material.................................................................................................................................................................. 26

Procedure..........................................................................................................................................................................................27

Sluggish system..............................................................................................................................................................................29

System operating hot...................................................................................................................................................................29

Excessive noise or vibration....................................................................................................................................................... 29

Motor operates normally in one direction only..................................................................................................................30

Improper output speed............................................................................................................................................................... 30

Low output torque........................................................................................................................................................................ 30

Overview........................................................................................................................................................................................... 32

Charge pressure relief valve..................................................................................................................................................32

Measuring charge pressure...................................................................................................................................................32

Adjusting charge pressure.................................................................................................................................................... 32

Minimum displacement limiter................................................................................................................................................ 33

Adjusting minimum displacement.................................................................................................................................... 33

Maximum displacement limiter................................................................................................................................................35

Series 51 motors .......................................................................................................................................................................36

Series 51-1 motors ...................................................................................................................................................................36

11008567 | AX00000013en-US0202 | 3