Bosch rexroth 11 Series Instruction Manual page 59

Table 15: Axial piston unit malfunction table
Malfunction
No or insufficient pressure
Pressure/flow fluctuations/
instabilities
Possible cause
Insufficient air bleeding of the hydraulic system Fill the axial piston unit, suction line for the
Faulty mechanical drive (e.g. defective coupling) Contact machine/system manufacturer
Drive power too low
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, impermissible filter in the
suction line
Hydraulic fluid not in optimal viscosity range
Insufficient pilot pressure or control pressure
Malfunction of the control device or controller
of the axial piston unit
Control of the control device defective
Wear or mechanical damage to the axial piston
unit
Output unit defective (e.g. hydraulic motor or
cylinder)
Insufficient air bleeding of the hydraulic system Fill the axial piston unit, suction line for the
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, impermissible filter in the
suction line
Valve and controller vibrate
Unstable control signal
Malfunction in the control devices or the
controller
Remedy
hydraulic pump and the reservoir
Completely air bleed the axial piston unit and
hydraulic system
Check correct installation position
Contact machine/system manufacturer
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
Machine/system manufacturer:
Check temperature range and use suitable
hydraulic fluid
Check pilot pressure or control pressure
Contact Bosch Rexroth Service
Contact Bosch Rexroth Service
Check control (contact machine/system
manufacturer or Bosch Rexroth Service)
Replace axial piston unit
Contact Bosch Rexroth Service
Contact machine/system manufacturer
hydraulic pump and the reservoir
Completely air bleed the axial piston unit and
hydraulic system
Check correct installation position
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
Optimize the adjustment of the controller of the
axial piston unit and the pressure limitation in
the hydraulic system
Contact machine/system manufacturer or
Bosch Rexroth Service
Contact Bosch Rexroth Service
RE 92511-01-B/2019-10-09, A15V(L)O Series 11, Bosch Rexroth AG
Troubleshooting 59/64