PUMP GP-WATER 0980071 - Caterpillar

Boom Lowering
To lower the boom, place the control lever into the Boom Down position. If the accumulator still has a charge, the boom will lower.If the boom fails to lower, the accumulator is empty. Use one of the following procedures to lower the boom.Boom Lowering With The Engine Stopped For Machines Not Equipped With A Boom Lowering Control Device
Use the following procedure when it is necessary to lower the boom when the engine is stopped or the hydraulic system is disabled.
Be sure no one is under or near the front implements before manually lowering the boom.Keep all personnel away from the boom drop area when lowering the boom with the engine stopped.
1. Loosen clamp (2) and disconnect overflow hose (1) from the side of the hydraulic tank.2. Slowly loosen fill/vent plug (3) on the top of the hydraulic tank to relieve the internal pressure in the tank. After the pressure has been relieved, remove plug (3). 3. Connect one end of hose (1) to screw (4) of the boom drift reduction valve. Put the other end of hose (1) into the opening on the hydraulic tank where plug (3) was removed.
Loosen screw (4) on the boom drift reduction valve a maximum of 1/2 turn to lower the boom.
4. Slowly loosen screw (4) a maximum of 1/2 turn to allow the hydraulic oil in the boom circuit to drain into the hydraulic tank. The boom will continuously lower until it is seated on the ground.5. After making sure that the front implement has lowered completely onto the ground, tighten screw (4) to 13 2 N m (9 1 lb ft).6. Disconnect hose (1) from screw (4). Hose may contain oil that has not completely drained.7. Connect hose (1) to the original position on the hydraulic tank and install plug (3) into the top of the tank. Tighten plug (3) to 68 7 N m (50 5 lb ft).8. Make any necessary repairs before placing the excavator back into service.Boom Lowering With The Engine Stopped For Machines Equipped With A Boom Lowering Control Device
Use the following procedure when it is necessary to lower the boom when the engine is stopped or the hydraulic system is disabled and the excavator is equipped with a boom lowering control device.
The boom load may cause the cylinder oil pressure to reach the relief pressure of the boom lowering control device when the boom is supported by one cylinder. This can cause the boom to lower suddenly.Be sure no one is under or near the front implements before manually lowering the boom.Keep all personnel away from the boom drop area when lowering the boom with the engine stopped.
A boom lowering control device (if equipped) is installed on each of the boom cylinders, as shown. The boom lowering control device allows the operator to manually lower the boom with the engine stopped. The boom lowering control device also functions to prevent the boom from dropping suddenly in case there is an oil