Troubleshooting 63/68
RE 92105-01-B/06.2017, A4CSG, Series 3x,
Bosch Rexroth AG
Table 14: Axial piston unit malfunction table
Malfunction
Possible cause
Remedy
Pressure/flow fluctuations/
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
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, foreign particles
in the suction line, suction filter too small or
blocked
Machine/system manufacturer: check the
system, for example, 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
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
Unstable control signal
Contact machine/system manufacturer or
Bosch Rexroth Service
Malfunction in the control devices or the
controller
Contact Bosch Rexroth Service
Excessive temperature of hydraulic
fluid and housing
Excessive inlet temperature at the axial piston
unit
Machine/system manufacturer: inspect
system, for example, malfunction in the cooler,
insufficient hydraulic fluid in the reservoir
Wrong setting or malfunction of the pressure
relief and pressure control valves (e.g. high-
pressure relief valve, pressure cut-off, pressure
controller)
Optimize the adjustment of the pressure relief
and pressure control valves of the axial piston
unit and the pressure safeguarding in the
hydraulic system
Contact Bosch Rexroth Service
Contact machine/system manufacturer
Flushing flow of the flushing valve too low
Contact Bosch Rexroth Service
Axial piston unit worn
Replace axial piston unit, contact
Bosch Rexroth Service
