Genie GTH-636 Service Manual page 115

June 2007
REV B
How to Adjust the Function Pump
Pressure
1 Install a 0 to 3500 psi / 0 to 250 bar pressure
gauge into test port 1 at the side of the
hydraulic tank.
Note: GTH-636, GTH-644, GTH-842 and GTH-
844: There are four test ports at the hydraulic tank.
Test port 1 is closest to the tank; test port 4 is
farthest from the tank.
Note: GTH-1048 and GTH-1056: There are six
test ports at the hydraulic tank. Test port 1 is
closest to the tank; test port 6 is farthest from the
tank.
2 Start the engine. Allow the engine to idle after
warming the engine to operating temperature.
3 Working at the hydraulic pump, loosen the set
screw securing the lower of the two hex
sockets of the DFR valve on the pump.
Note: The hydraulic pump is located on the top of
the transmission at the cab side.
a pump
b DFR valve
Part No. 97487 GTH-636 • GTH-644 • GTH-842 • GTH-844 • GTH-1048 • GTH-1056
4 Fully press and release the brake pedal 3 times,
then observe the reading on the pressure
gauge. Note the pressure. Refer to Section 2,
Specifications .
Result: The pressure meets specification.
Securely tighten the set screw. Proceed to step
6.
Result: The pressure fails to reach
specification. Proceed to step 5.
5 Adjust the lower hex socket of the DFR valve.
Turn it clockwise to increase the pressure or
counterclockwise to decrease the pressure.
Repeat this procedure beginning with step 4.
6 Turn the machine off. Remove the pressure
gauge.
a b
Section 4 • Repair Procedures
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.
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