82/88
Hägglunds DUc Drive unit
| Troubleshooting
Bosch Rexroth AB, Version 06.2020, RE 15326-WA
Causes Of Trouble And Its Effect In The Hydraulic Installation
Source of trouble,
effects
Mechanical Drive
Suction Line
Pump
Pressure Line
Return Line
Power Take-off
either does not
turn at all or
too slowly. (no
delivery flow
or insufficient
delivery flow)
1. Coupling
wrongly aligned.
2. Coupling loose.
3. Coupling
defective.
4. Loose mounting
on pump and/or
motor.
5. Other
transmission
elements loose.
6. Pump or motor
defective.
7. Direction of
rotation wrong.
Suction resistance
is excessive :-
1. Valve in the
suction line is part
open.
2. Suction filter
clogged or too
small (if fitted).
3. Suction line
blocked or leaking.
4. Suction line is
sized wrong.
5. Fluid level too
low.
1. Internal leakage
due to wear.
2. Pump defective.
3. Inlet and return
lines wrongly
connected.
1. Leakages.
2. Excessive line
resistance.
3. Pressure filter
blocked.
1. Excessive line
resistance.
2. Filter blocked.
Excessive
operating
temperature
1. Reduction in
efficiency due to
wear.
2. With variable
pumps, the pump
control system is
defective.
3. Rotational speed
and/or delivery
excessive.
1. Pipe bore is
too small, causing
high frictional
resistances.
2. Pressure filter
blocked.
1. Pipe bore is
too small, causing
high frictional
resistances.
2. Return filter
blocked.
Line shocks when
switching takes
place.
1. Line mounts are
missing or loose.
2. Poor
installation.
3. Pipe bore too
small.
4. Installation not
bled.
5. Oil volume in
lines is excessive
1. Lines loose.
The pump
switches on and
off too often.
1. Pump defective.
2. In the case
of accumulator
systems, the pump
is incorrectly sized.