Troubleshooting 59/68
RE 92004-01-B/05.2017, A4VG Series 40,
Bosch Rexroth AG
14.2 Malfunction table
Table 13: 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
Insufficient suction conditions, e.g. insufficient
dimensioning of the suction line, viscosity of
the hydraulic fluid too high, suction height too
high, suction pressure too low, contaminants
in the suction line, suction filter too small or
blocked, etc.
Machine/system manufacturer: Check the
system, e.g. optimize inlet conditions, use
suitable hydraulic fluid
Fill the suction line with hydraulic fluid
Remove foreign particles from the suction line
Check the filter system and change the filter as
necessary
Drive speed too high
Machine/system manufacturer: reduce drive
speed
Wrong direction of rotation
Machine/system manufacturer: check correct
direction of rotation, see chapter 7.4.1 “Prepara-
tion” on page 34
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
coupling
Mount assembled parts according to the
information provided by the coupling or fitting
manufacturer
Oscillate pressure limitation and pressure
control valves of the axial piston unit (boost-
pressure relief valve, high-pressure relief valve,
pressure cut-off)
Air bleed the axial piston unit and hydraulic
system
Contact Bosch Rexroth Service:
Optimize the setting of the pressure limitation
and pressure control valves
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