Malfunction
Possible cause
Remedy
No or too less pres‐
sure.
Defective mechanical drive (e.g. defective cou‐
pling).
Machine or system manufacturer.
Drive power too low.
Machine or system manufacturer.
Unsufficient suction behavior, e.g. air in the suc‐
tio port, unsufficient diameter of the suction port,
too high viscosity of the hydraulic fluid, too high
suction height, too low suction pressure, foreign
bodies in the suction port.
Machine- or system manufacturer (e.g. optimize
intake relations, use suitable hydraulic fluid).
Completely bleed the axial piston unit, fill the
suction port with hydraulic fluid.
Remove foreign bodies in the suction port.
Hydraulic fluid not in optimum viscosity range.
Use suitable hydraulic fluids (machine- or sys‐
tem manufacturer).
External control of the adjusting device defec‐
tive.
Check external control unit (machine- or system
manufacturer).
To low control pressure or set pressure.
Check control pressure or set pressure and
contact Bosch Rexroth service.
Malfunction of adjusting device or of the control‐
ler of the axial piston unit.
Contact Bosch Rexroth service.
Wear of axial piston unit.
Change axial piston unit and contact Bosch
Rexroth service.
Mechanical damage of axial piston unit (e.g.
damaged bearings).
Change axial piston unit and contact Bosch
Rexroth service.
Drive unit defective (e.g. hydraulic motor or -cyl‐
inder).
Machine or system manufacturer.
Pressure or volume
current fluctuation
Axial piston unit not or unsufficiently ventilated. Completely ventilate axial piston unit
Unsufficient suction behavior, e.g. air in the suc‐
tio port, unsufficient diameter of the suction port,
too high viscosity of the hydraulic fluid, too high
suction height, too low suction pressure, foreign
bodies in the suction port.
Machine- or system manufacturer (e.g. optimize
intake relations, use suitable hydraulic fluid).
Machine- or system manufacturer (e.g. optimize
intake relations, use suitable hydraulic fluid).
Remove foreign bodies in the suction port.
Too high temperature
of hydraulic fluid and of
the housing
Too high inlet temperature on the axial piston
unit.
Machine or system manufacturer: Check sys‐
tem, e.g. malfuction of the cooling unit, too less
hydraulic fluid in the pan.
Malfunction of pressure control valve (e.g. high-
pressure limitation valve, pressure cutoff, pres‐
sure control).
Contact Bosch Rexroth service.
Wear of axial piston unit.
Change axial piston unit and contact Bosch
Rexroth service.
Change axial piston
unit and contact Bosch
Rexroth service.
Command value not firm.
Machine or system manufacturer.
Resonances in the tank line.
Machine or system manufacturer.
Malfunction of setting device or of the controller. Contact Bosch Rexroth service.
Tab. 13-2:
Malfunctions axial piston unit
Bosch Rexroth AG
DOK-SYTROX-MPES2******-IT01-EN-P
Rexroth Sytronix FcP 50xx/70xx Motor-Pump Unit MPES2
94/143
Troubleshooting
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