Troubleshooting 61/68
RE 92004-01-B/05.2017, A4VG Series 40,
Bosch Rexroth AG
Table 13: Axial piston unit malfunction table
Malfunction
Possible cause
Remedy
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
Completely air bleed the axial 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, 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
Hydraulic fluid not in optimum viscosity range
Machine/system manufacturer:
check temperature range and use suitable
hydraulic fluid
Insufficient boost pressure
Check boost pressure
Contact Bosch Rexroth Service
Insufficient pilot pressure or control pressure
Check pilot pressure or control pressure
Contact Bosch Rexroth Service
Malfunction of the control device or controller
of the axial piston unit
Contact Bosch Rexroth Service
Control of the control device defective
Check control (contact machine/system
manufacturer or Bosch Rexroth Service)
Wear or mechanical damage to the axial piston
unit
Replace axial piston unit
Contact Bosch Rexroth Service
Output unit defective (e.g. hydraulic motor or
cylinder)
Contact machine/system manufacturer
