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Control blocks for mobile applications
| Troubleshooting
Bosch Rexroth AG, RE 64025-B/2021-08-12
Table 8: Malfunction table
Malfunction
Possible cause
Remedy
Working movement is
irregular
Air in the hydraulic fluid
Air bleed hydraulic system, see page 36.
Dirt or foreign particles in the hydraulic
fluid or the control block
Filter the hydraulic fluid or replace it.
Clean the interior of the control block.
The viscosity of the hydraulic fluid is too
low
Reduce the temperature of the hydraulic fluid.
The viscosity of the hydraulic fluid is too
high
Increase the temperature of the hydraulic fluid.
The flow is too low.
Make sure that the flow is adequate.
No function
Control block connected incorrectly
Correct the hydraulic and/or electrical connections.
Repair the actuation
Control spool faulty
Check the tightening torques of the tie rods, refer to the
spare parts list.
Version:
mechanical actuation
Impossible to
deflect control spool
mechanically
Tie rods were tightened at a tightening
torque that was too high/at different
tightening torques
Undo the nuts of the tie rods and tighten them to the
specified tightening torque.
Oil temperature is too high or the
temperature difference between the
hydraulic fluid and the control block is too
great. This means that sticking occurs due
to the different thermal expansion of the
control spool and the control block.
Check the cooler function, the oil supply and the pump
pressure in the neutral position.
Avoid a temperature shock; for information on this
topic, refer to the "Technical data sheet".
Any dirt or foreign particles that enter at
installation of the ports leading to the
actuator jam the control spool.
Try to switch the valve several times by actuating the
hand lever or the pilot control.
Carry out a visual inspection of the ports to the
actuator and remove the foreign particles using a
solenoids and a tweezers. If foreign particles are
jammed, renew the valve housing.
Control spool not
operating or goes back
too slowly
Control spool is jammed
In the case of a malfunction, see "Not possible to
deflect control spool mechanically" above
Control spool is held by flow force caused
by high oil flow
Reduce the oil flow from the consumer to the reservoir.
Version: Electrohydraulic
actuation
Control spool does not
react to electrical control
at all or only reacts on a
delayed basis
No solenoid current at all or it is too low,
wrong operating point (solenoid current not
adapted correctly to oil flow)
Check voltage supply and Q/I operating point,
see "Technical data sheet". Check plug-in connection.
Pilot control valve or solenoid valve not
functioning
Renew the pilot control valve or the solenoid valve.
Undersupply (pump pressure is too low).
Provide the minimum pump pressure, see
"Technical data sheet".
Undersupply (pump pressure is too low). Provide the
minimum pump pressure, see "Technical data sheet".
Pilot oil supply is jammed
Remove the pilot oil supply and replace it with a
new one.
Pilot control valves are contaminated
Renew the pilot control valve.
Version:
hydraulic actuation
Undersupply (pump pressure is too low).
Provide the minimum pump pressure, see "Technical
data sheet".
No pilot pressure present
Check the pilot oil supply
With valves in parallel
operation: No pressure
or no oil flow on the
consumer when the
control spool is deflected,
major delay in pressure
build-up
Oil flow flows to consumer at minimum
pressure due to undersupply
Increase the pump oil flow by raising the rotational
speed or using a bigger pump or reduce the amount of
flow to the consumer using a quantity regulator.
