Troubleshooting 69/72
RE 92050-01-X-B1/2019.08.23, Axial piston variable pump A4VSO, BoschRexrothAG
Table 18: Axial piston unit malfunction table
Malfunction Possible cause Remedy
No orinsufficient pressure Insufficient air bleeding ofthehydraulic system Axial piston unit, suction line for the
hydraulicpump and filling the reservoir
Completely air bleed theaxial piston unit and
hydraulic system
Check correct installation position
Faulty mechanical drive (e.g. defective coupling) Contact machine/system manufacturer
Drive power too low Contact machine/system manufacturer
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, etc.
Machine/system manufacturer: Check
thesystem, e.g. optimize inlet conditions,
usesuitable hydraulic fluid
Fill thesuction line with hydraulic fluid
Remove foreign particles from thesuction line
Check the filter system and change the filter
asnecessary
Hydraulic fluid not inoptimal viscosity range Machine/system manufacturer:
Check temperature range and use suitable
hydr
aulic fluid
Insufficient boost pressure Check boost pressure
Contact BoschRexrothservice
Insufficient pilot pressure orcontrol pressure Check pilot pressure orcontrol pressure
Contact BoschRexrothservice
Malfunction ofthecontrol device orcontroller
oftheaxial piston unit
Contact BoschRexrothservice
Control ofthecontrol device defective Check control (contact machine/system
manufacturer or BoschRexrothservice)
Wear ormechanical damage tothe
axialpistonunit
Replace axial piston unit
Contact BoschRexrothservice
Output unit defective (e.g. hydraulic motor
orcylinder)
Contact machine/system manufacturer