September 2017
Part No. 57.4400.9219
GTH-1256 AF
4-31
Section 4 • Repair Procedures
How to Adjust the Boom
and Steering Function Pump
Pressure Compensator
Note: Two people will be required to perform this
procedure.
1 Connect a 0 to 5000 psi / 0 to 350 bar pressure
gauge to port TP1.
2 Start the engine and allow the engine to run at
low idle.
3 Fully retract the boom.
4 Continue to activate the boom retract function
and observe the pressure reading on the
pressure gauge.
5 Turn the pressure relief valve on the function
manifold incrementally and ensure that the
pressure gauge reading begins to increase.
6 Stop turning the valve on the function manifold
when the pressure gauge reading is stable.
Result: the pressure gauge reads 4350 psi /
300 bar. The pump is good. Proceed to step 9.
Pressure is not within speci
fi
cation.
The pressure setting needs to be adjusted.
Proceed to step 7.
7 Loosen the set screw for the pressure
compensator adjustment screw on the pump.
8 Adjust the pressure compensator pressure.
Turn the adjustment screw clockwise to
increase the pressure; turn the adjustment
screw counterclockwise to decrease the
pressure. Tighten the set screw.
WARNING
Component damage hazard. Do
not adjust the pressure
compensator higher than
speci
fi
ed.
9 Turn the pressure relief valve on the function
manifold again until the pressure gauge reads
4060 psi / 280 bar.
10 Turn the engine off and remove the pressure
gauge.
HYDRAULIC PUMPS
