Genie GTH-636 Service Manual page 159

June 2007
REV B
Fork Level Function
Symptom A:
Forks self-level at slower rate than boom is
descending
Check the Tilt Relief Valve
1 Start the engine and allow the engine to idle.
2 Level the forks.
3 Stop the engine.
4 Tag and disconnect the hydraulic hoses at the
tilt limiter manifold. Cap the fittings on the
manifold. Connect the hoses together and
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.
5 Start the engine and allow the engine to idle.
6 Activate the boom up and boom down
functions.
Result: The machine functions correctly.
Replace the relief valve of the tilt limiter
manifold (schematic item BA).
Result: The machine does not function
correctly. Troubleshoot the fork level cylinder
manifold components (schematic items RA, RB
and RC) OR check the cylinder for internal
leakage.
Part No. 97487 GTH-636 • GTH-644 • GTH-842 • GTH-844 • GTH-1048 • GTH-1056
Symptom B:
Forks self-level at a faster rate than the boom is
descending.
1 Remove the load from the forks.
2 Start the engine and allow the engine to idle.
3 Level the forks.
4 Stop the engine.
5 Tag and disconnect the two hydraulic hoses of
the boom from the tee fittings at ports C1 and
C2 of the dual pilot check manifold. Cap the
fittings.
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.
6 Tag and disconnect the hydraulic hoses from
the fittings at ports V1 and V2 of the dual pilot
check manifold. Cap the fittings.
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.
7 Connect the hydraulic hose of port C1 to the
hydraulic hose of port V1. Torque to
specification. Refer to Section 2, Specifications.
8 Connect the hydraulic hose of port C2 to the
hydraulic hose of port V2. Torque to
specification. Refer to Section 2, Specifications.
9 Start the engine and allow the engine to idle.
Section 5 • Troubleshooting
TROUBLESHOOTING
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