6-4 Troubleshooting
022-00028AE Operation and Maintenance Manual
HYDRAULIC SYSTEM
Problem
Cause
Remedy
None of the controls function
(loud noise from pumps).
Hydraulic pump failed.
Contact your Daewoo
dealer.
Low hydraulic oil level.
Add hydraulic oil as
required.
Suction line plugged or damaged.
Clean or replace as
required.
None of the controls function (no
noise from pumps).
Pilot pump failure.
Contact your Daewoo
dealer.
Cutoff solenoid valve failed.
Replace solenoid.
Relief cartridge of pilot parking valve
stuck.
Clean or replace as
required.
Safety limit switch is ON.
Adjust limit switch
clearance.
All actuators have low power.
Low hydraulic oil level.
Add hydraulic oil as
required.
Suction filter clogged.
Clean filter.
Hydraulic pumps faulty.
Contact your Daewoo
dealer.
Main relief pressure too low.
Contact your Daewoo
dealer.
Hydraulic pumps cavitating.
Bleed air from hydraulic
pumps.
Only one or two actuators have
little or no power.
Overload relief pressure too low.
Reset pressure.
Make-up check valve leaking.
Clean or replace as
required.
Control valve spool faulty.
Replace valve spool.
Dirt in valve spool.
Clean or replace as
required.
Actuator failed.
Repair or replace as
required.
Cylinder seal failed.
Repair or replace as
required.
Cylinder rod damaged.
Repair or replace as
required.
Remote control valve failed.
Replace control valve.
Wrong pilot line connection.
Reconnect pilot lines.