Pilot Pressure; Adjustment And Testing - Doosan DX140R Shop Manual

PILOT PRESSURE

Adjustment and Testing

This procedure should be done with two people. To reduce
the chance of accident or unintended start-up, one person
should remain at the operator's control stand while checks
and adjustments are made.
Vent hydraulic pressure from the reservoir before breaking the
seal on fittings to install two in-line "T-style" adapters and test
gauges (60 bar/1,000 psi) at the gear pump outlet port, and at
the joystick control valve pilot line.
Start the engine and turn the engine speed control dial to the
maximum setting. After the excavator has been operated long
enough to reach normal operating temperature, back off the
engine control dial to minimum rated rpm speed. With all
controls in neutral, make sure the left console control stand is
locked in the down (operating) position and check pressure at
the gear pump outlet port and at the joystick.
If gear pump pressure is outside the tolerance specified in the
table, adjust gear pump relief pressure by loosening the lock nut
and turning the set screw in (clockwise) to increase pressure, or
turning it out to decrease it.
Be aware that serial number changes and variation in
NOTE:
the joystick assemblies used on different excavators
could produce slight change in actual performance
characteristics. Comparison of part numbers to serial
numbers stamped on your assembly may be
required, if questions or doubt exists.
IMPORTANT
Top off the hydraulic fluid reservoir if there is any
measurable loss of hydraulic oil during test gauge and
adapter fitting installation.
Engine RPM
Minimum Speed Setting (full left)
on Speed Control Dial
Hydraulic System Troubleshooting, Testing and Adjustment
Page 16
WARNING
Pilot Pressure @ Pump
(580 ± 73 psi)
40 ± 5 bar
Pilot Pressure - Joystick
40 ± 5 bar
(580 ± 73 psi)
SP001942