Brake Functions - Genie GTH-636 Service Manual

June 2007
REV A
1-6

Brake Functions

Service Brakes
Symptom:
Brakes dragging (not releasing)
1 Tee in a 0 to 1000 psi / 0 to 100 bar pressure
gauge at port A of the brake actuator at the
brake pedal assembly.
2 Start the engine and allow the engine to idle. Do
not touch the brake pedal.
Result: The gauge indicates 0 psi / 0 bar. The
actuator is good.
Result: The gauge indicates more than
0 psi / 0 bar. The actuator is faulty. Replace the
brake actuator.
Symptom:
Brakes slow to apply OR apply too quickly
1 Tee in a 0 to 1000 psi / 0 to 100 bar pressure
gauge at port A of the brake actuator at the
brake pedal assembly.
2 Start the engine and allow the engine to idle.
3 Press down on the brake pedal.
Result: The gauge indicates
600 to 650 psi / 41.4 to 44.8 bar. The actuator
is good.
Result: The gauge indicates less than
600 psi / 41.4 bar. The actuator is faulty.
Replace the brake actuator.
Result: The gauge indicates more than
650 psi / 44.8 bar. The actuator is faulty.
Replace the brake actuator.
Part No. 97487 GTH-636 • GTH-644 • GTH-842 • GTH-844 • GTH-1048 • GTH-1056
Parking Brake
Symptom:
Parking brake does not hold OR does not release
1 Locate the parking brake manifold.
Note: The parking brake manifold is the outboard
of the two manifolds located inside the frame rail
next to the operator's compartment.
2 Tag, disconnect and plug the hydraulic hoses at
ports 1 and 2 of the parking brake 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.
3 Install a hose measuring 3 feet / 1 m into each
port and tighten.
4 With the open ends of both hoses into a 5
gallon container, start the engine.
Section 5 • Troubleshooting
TROUBLESHOOTING
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