Troubleshooting 91/104
RE 92076-01-B/10.2017, A4... with HS5E pilot control valve/Series 3x,
Bosch Rexroth AG
Table 26: 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, impermissible filter in the
suction line
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
Hydraulic fluid not in optimum viscosity range
Machine/system manufacturer:
check temperature range and use suitable
hydraulic fluid
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
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, contaminants
in the suction line, impermissible filter in the
suction line
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
Valve and controller vibrations
Optimize the adjustment of the axial piston
unit and the pressure limitation in the hydraulic
system
Unstable control signal
Contact machine/system manufacturer or Bosch
Rexroth Service
Malfunction in the control devices or the
controller
Contact Bosch Rexroth Service