LEVER & BEARING AS 5426151 - Caterpillar

Machine Without a Boom Lowering Control Valve
Be sure no one is under or near the work tools before manually lowering the boom. Keep all personnel away from the boom drop area when lowering the boom with the engine stopped in order to avoid possible personal injury.
When you must manually lower the boom due to engine shutdown, use the following procedure:Note: Keep all personnel away from the boom when you are lowering the boom.
Illustration 1 g00580815
Rear of the Main Control Valve
(1) Locknut
(2) Screw
Slowly loosen locknut (1).
Loosen screw (2) to a maximum of 1/2 turn. The boom will now start to lower.
After the work tools have been lowered to the ground, tighten the screw and the locknut.
Consult your Caterpillar dealer and make any necessary repairs. After completion of the manual boom lowering, make necessary repairs before you operate the machine again.Machine With a Boom Lowering Control Valve (If Equipped)
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. The boom lowering control valve allows the operator to manually lower the boom. Use the following procedure if the machine is equipped with a boom lowering control valve.
Illustration 2 g01924625The boom lowering control valve is located near the base of the boom.
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 work tool has been lowered onto the ground. Tighten check valve (2) to a torque of 2.25 0.25 N m (1.66 0.18 lb ft).
Tighten locknut (1) to a torque of 4 0.5 N m (3 0.37 lb ft).
Before you begin operating the machine, make any necessary repairs. For additional information, consult your Caterpillar dealer.