Hydraulic system – Lull 944E-42 Service Manual User Manual
Page 311
8.59
Model 644E-42/944E-42
Rev. 6/04
Hydraulic System
Not
OK
If the pump is not
functioning properly
Not
OK
Inspect the check valve in the
cooler hydraulic line.
If the cooler is not cooling
the oil, check that the
radiator and cooler are not
clogged or obstructed.
Replace check valve.
If OK
If OK
Refer to Section 9.14.4, “Dual
Clean radiator and cooler.
Not
OK
Repair/replace suction line.
Check suction line from
reservoir to the pump.
NOTE:
When checking pressures in
circuits, refer to Section 8.7,
“Hydraulic System Testing,” for
correct pressure readings.
Not
OK
Repair/replace pump.
Check pump.
If OK
Before troubleshooting any
hydraulic circuit, ALWAYS
begin by checking the
following:
1. Hydraulic oil level in the
reservoir
2. All hoses, tubes, fittings
for leaks, kinks,
interference, etc.
3. Air in the lines