Hydraulic Pump - Genie GTH-636 Service Manual

Section 5 • Troubleshooting
TROUBLESHOOTING
1-2

Hydraulic Pump

Symptom:
Laboring engine; pump is constantly trying to build
pressure.
Check the Pump
1 Tag, disconnect and plug the smaller JIC hose
at the top of the hydraulic pump.
Bodily injury hazard. Spraying
hydraulic oil can penetrate and
burn skin. Loosen hydraulic
connections very slowly to allow
the oil pressure to dissipate
gradually. Do not allow oil to
squirt or spray.
2 Install a hose onto the open port and tighten.
Place open end of hose into 5 gallon container.
3 Start the engine and run for 1 minute.
4 Stop the engine. Measure the fluid.
Result: Fluid volume is one gallon or less. The
pump is good. Proceed to step 5.
Result: Fluid volume is greater than one gallon.
The pump is faulty. Replace the pump.
5 - 4 GTH-636 • GTH-644 • GTH-842 • GTH-844 • GTH-1048 • GTH-1056
Check the Main Valve
5 Tag and disconnect the 1.5 inch main valve
hose from the collector manifold at the top of
the hydraulic tank. Drain the hose into a
container.
6 Place open end of hose into 5 gallon container.
7 Start the engine.
Result: No fluid is draining from the hose. The
main valve is good. Proceed to step 10.
Result: Fluid is draining from the hose. Inspect
the main valve Y-plug. Proceed to the next
step.
8 Stop the engine. Remove the Y-plug from the
top of the main valve. Inspect for cracks, cuts
or breaks in the o-ring or teflon ring.
Result: Cracks, cuts or breaks are not
observed. The Y-plug is in good condition.
Proceed to the next step.
Result: Cracks, cuts or breaks are observed.
Replace the o-ring or teflon ring.
Bodily injury hazard. Spraying
hydraulic oil can penetrate and
burn skin. Loosen hydraulic
connections very slowly to allow
the oil pressure to dissipate
gradually. Do not allow oil to
squirt or spray.
9 Remove the manifold relief valve (schematic
item AD) from the main valve manifold. Inspect
for cracks, cuts or breaks in the seals.
Result: Cracks, cuts or breaks are not
observed. Replace the relief valve.
Result: Cracks, cuts or breaks are observed.
Replace the seals.
Bodily injury hazard. Spraying
hydraulic oil can penetrate and
burn skin. Loosen hydraulic
connections very slowly to allow
the oil pressure to dissipate
gradually. Do not allow oil to
squirt or spray.
June 2007
REV A
Part No. 97487