BOOM EXTEND CYLINDER SLOW OR DOES NOT EXTEND OR RETRACT - continued

TM 10-3930-673-20-1

WARNING

Hydraulic oil in the system can be under pressures over 3000 psi with 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 live pressure. Relieve

pressure in hydraulic oil tank by loosening filler cap very slowly. Failure to follow these precautions could result in serious

personal injury.

At operating temperatures, hydraulic oil is hot and under pressure. Hot oil can cause injuries. Allow hydraulic oil to cool before

disconnecting any hydraulic lines.

HYDRAULIC JOYSTICK CONTROL VALVE

PRESSURE TEST

(1) Place hydraulic joystick in neutral

position and check the pressure at the

hydraulic joystick control valve "p" port.

(a) If hydraulic oil pressure is null go to

Step (2) below.

(b) If not, replace joystick control valve

(Para 18-11).

(2) Place hydraulic joystick in raise

position and then in lower position.

Check pressure at input lines to

hydraulic joystick control valve.

(a) If hydraulic oil pressure is at 1700

TR01815

to 1800 psi (11721 to 12411 kPa),

notify Direct Support of faulty

extend cylinder.

(b) If hydraulic oil pressure is not at

1700 to 1800 psi (11721 to 12411

kPa), shut down engine (TM 10-

3930-673-10) and replace

hydraulic joystick control valve.

TR01264

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