BLOCK-PULLER 5F7344 - Caterpillar

Machine with a Boom Lowering Control Valve
Boom load may cause cylinder oil pressure to reach relief pressure of the boom lowering control device when the boom is supported by one cylinder. Boom can lower suddenly, causing possible injury or death.To avoid possible injury or death, be sure no one is under or near the work tool before manually lowering the boom.Keep all personnel away from the boom drop area when lowering the boom with the engine stopped.
If the engine is shut down or the hydraulic system is disabled, the operator can still lower the boom. Use the following procedure if the machine is equipped with a boom lowering control valve.
Illustration 1 g00101574
The boom lowering control valve is at the back of the base of the boom. The boom lowering control valve allows the operator to manually lower the boom if the engine is stopped. The boom lowering control valve also ensures that the boom does not fall suddenly if there is an oil leak in the hydraulic line of the boom.
Illustration 2 g01661913
Loosen locknut (1) .
Slowly turn check valve (2) counterclockwise until the check valve stops. The boom will lower to the ground.
Make sure that the implement has been completely lowered onto the ground. Turn check valve (2) to the Closed position.
Tighten locknut (1) to a torque of 55 10 N m (41 7 lb ft).
Before you begin operating the machine, make any necessary repairs.For additional information, consult your Caterpillar dealer.