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TM10-3930-660-20
18-6.
MAIN CONTROL VALVE ASSEMBLY - ADJUST/REPLACE (Cont d)
4. ADJUST MAIN RELIEF VALVE PRESSURE
BETWEEN 2,750 AND 2,850 psi.
a. Operate boom extend, retract,
hoist or lower function until
hydraulic oil is passing over
relief valve.
Continue to hold
hydraulic lever in that position
so oil passes over relief valve
during relief valve adjustment.
b. Turn adjusting screw counter-
clockwise (out) until pressure on
gauge reads between 2,750 and
2,850 psi.
c. Release hydraulic function lever.
d. Hold adjusting screw in position
and tighten jam nut (4).
Install
acorn nut (3).
5. STOP ENGINE, TM10-3930-660-10.
Hydraulic oil in the system can be under
pressures over 3000 psi with the engine
OFF. ALWAYS relieve pressure in
hydraulic lines before attempting to
remove any component in the hydraulic
system. With engine OFF, starter switch
in RUN position, and MLRS attachment on
the ground, move control levers through
all operating positions several times to
relieve line pressure, Relieve pressure
in hydraulic oil tank by loosening
filler cap very slowly. Failure to
follow these precautions could result
in
6.
serious personal injury.
REMOVE PRESSURE GAUGE.
Unscrew pressure gauge from main
relief valve plug assembly port (2).
7.
8.
INSTALL MAIN RELIEF VALVE PLUG
ASSEMBLY .
Screw main relief valve plug
assembly (1) into port (2) and
tighten.
REPLACE TRANSMISSION COVER,
PARA. 16-6.
18-26
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