50/56 Troubleshooting
Bosch Rexroth AG
, A2FM/A2FE/A2FMT Series 70, RE 91071-01-B/06.2018
14.2 Malfunction table
Table 18: Axial piston unit malfunction table
Malfunction
Possible cause
Remedy
Unusual noises
Insufficient air bleeding of the hydraulic system
Fill the axial piston unit, suction line for the
hydraulic pump and the reservoir
Completely air bleed the axial piston unit and
hydraulic system
Check correct installation position
Output speed too high
Machine/system manufacturer: reduce output
speed
Improper mounting of the axial piston unit
Check the mounting of the axial piston unit
according to the specifications of the machine/
system manufacturer (observe tightening
torques)
Improper mounting of assembled parts,
hydraulic lines or improper installation of the
clutch
Mount assembled parts according to the
information provided by the clutch or fitting
manufacturer
Mechanical damage to the axial piston unit
(e.g. bearing damage)
Replace axial piston unit
Contact Bosch Rexroth Service
Increased, unusual vibration
Bearings worn
Contact Bosch Rexroth Service
No or insufficient pressure
Insufficient air bleeding of the hydraulic system
Fill the axial piston unit, suction line for the
hydraulic pump and the reservoir
Check correct installation position
Faulty mechanical output drive (e.g. defective
clutch)
Contact machine/system manufacturer
Drive power too low
Contact machine/system manufacturer
Wear or mechanical damage to the axial piston
unit
Replace axial piston unit
Contact Bosch Rexroth Service
Drive unit defective (e.g. hydraulic pump)
Contact machine/system manufacturer
Pressure/flow fluctuations or
instabilities
Insufficient air bleeding of the hydraulic system
Fill the axial piston unit, suction line for the
hydraulic pump and the reservoir
Completely air bleed the axial piston unit and
hydraulic system
Check correct installation position
Rotational speed or torque cannot
be reached
Insufficient flow in hydraulic pump
Check function of the hydraulic pump
Hydraulic fluid not in optimum viscosity range
Machine/system manufacturer:
check temperature range and use suitable
hydraulic fluid
Wear or mechanical damage to the axial piston
motor
Replace axial piston unit
Contact Bosch Rexroth Service
Wear or mechanical damage to the hydraulic
pump
Replace hydraulic pump
Contact Bosch Rexroth Service
Wrong direction of rotation
Check function of the hydraulic pump
Machine/system manufacturer: check correct
direction of rotation; see chapter 7.4.1
“Preparation” on page 28
