BIT-END 3708743 - Caterpillar

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 g00784618
(1) Bolts (2) Washers (3) Cover
Remove four bolts (1) , four washers (2) , and cover (3) from the top of the hydraulic tank.
Illustration 2 g00789011
(4) Pressure cap
Slowly loosen pressure cap (4) on the top of the hydraulic tank until internal pressure in the hydraulic tank has been completely relieved. Remove pressure cap (4) .
Illustration 3 g00789031
(5) Clamp (6) Hose
Loosen clamp (5) and disconnect hose (6) from the hydraulic tank.
Illustration 4 g00789010
(6) Hose (7) Screw
Connect an end of hose (6) to screw (7) . Put the other end of hose (6) into the opening for the pressure cap.
Slowly loosen screw (7) by a maximum of 1/2 turn. This allows the hydraulic oil in the boom circuit to drain into the hydraulic tank. The boom will now start to lower.
Make sure that the work tool has lowered all the way to the ground. Tighten screw (7) to a torque of 13 2 N m (9 1 lb ft).
Disconnect hose (6) from screw (7) . Do not allow the oil that is contained in hose (6) to spill.
Connect hose (6) to the original position on the hydraulic tank and install pressure cap (4) securely.After completion of the manual boom lowering, make necessary repairs before you operate the machine again.