Genie GTH-636 Service Manual page 157

June 2007
REV B
Lift Not Functional
1 Tag and disconnect the hydraulic hoses at the
dual pilot check manifold. Cap the fittings on the
manifold. Connect together both hoses from the
CA side of the manifold AND connect together
both hoses from the CB side of the manifold.
Torque to specification. Refer to Section 2,
Specifications.
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 Start the engine and allow the engine to idle.
3 Activate the boom up function.
Result: The machine functions correctly.
Replace the check valves of the dual pilot
check valve manifold (schematic items CA and
CB) OR replace the dual pilot check valve
manifold.
Result: The machine does not function
correctly. Proceed to step 4.
Crushing Hazard. The load on the
forks could fall when lowering the
boom due to bypassing the fork
self-leveling function, resulting in
death or serious injury and
property damage. Do not allow
anyone to stand anywhere near
the area below or in front of the
boom when performing this
procedure.
Part No. 97487 GTH-636 • GTH-644 • GTH-842 • GTH-844 • GTH-1048 • GTH-1056
4 Lower the boom to the stowed position. Stop
the engine.
5 Replace the check valve at the barrel end of the
fork level cylinder (schematic item RA) OR
troubleshoot the dual pilot check circuit.
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.
Section 5 • Troubleshooting
TROUBLESHOOTING
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