HUB AS 1465831 - Caterpillar

Cylinders equipped with load control valves can remain pressurized, even with hoses removed.Failure to relieve pressure before removing a load control valve or disassembling a cylinder can result in personal injury or death.Ensure all pressure is relieved before removing a load control valve or disassembling a cylinder.
Care must be taken to ensure that fluids are contained during performance of inspection, maintenance, testing, adjusting and repair of the product. Be prepared to collect the fluid with suitable containers before opening any compartment or disassembling any component containing fluids.Refer to Special Publication, NENG2500, "Caterpillar Tools and Shop Products Guide" for tools and supplies suitable to collect and contain fluids on Caterpillar products.Dispose of all fluids according to local regulations and mandates.
Relieving Pressure in the Hydraulic System
Before you remove any hydraulic components from the machine make sure that all hydraulic pressure in the hydraulic system is relieved. Before you start any maintenance on the boom, support the boom on a suitable stand. Refer to the "Tools and Shop Products Guide" for information on stands that are available.
Lower the work tool to the ground.
Shut off the engine.
In order to release any pressure from the hydraulic tank, you must loosen the hydraulic tank filler cap slowly.
Tighten the filler cap.
Relieve the system pressure from the load control valves and cylinders.Load Control Valve Locations
Care must be taken when you are removing counterbalance valves from load control valves. Counterbalance valves are installed in the load control valves on the following cylinders:
Telescoping Cylinder
Boom Cylinder (Boom Raise/Lower)
Stabilizer Cylinder (if equipped)
Frame Leveling Cylinder (if equipped)
Boom Cylinder (Coupler Tilt)The load control valves are an integral part of the telescoping cylinders. The load control valves can not be removed from the cylinders.Telescoping Cylinder
Illustration 1 g00747772
Load Control Valve (1) Counterbalance valveBoom Cylinder (Boom Raise/Lower)
Illustration 2 g00747770
Load Control Valve (1) Counterbalance valveStabilizer Cylinder
Illustration 3 g00747775
Load Control Valve (1) Counterbalance valveFrame Leveling Cylinder
Illustration 4 g00747776
Load Control Valve (1) Counterbalance valveBoom Cylinder (Coupler Tilt)
Illustration 5 g00721000
Load Control Valve (1) Load control valveThe load control valve (1) on the cylinder for the coupler tilt does not have a counterbalance valve. Slowly loosen the mounting bolts for the load control valve in order to release any residual hydraulic pressure in the load control valve. The bolts should be loosened sequentially. Take care to avoid any oil that is released from the valve.Relieving Pressure from the Load Control Valves
This procedure may be used in the following operations:
Boom lowering without hydraulic power
Boom retract without hydraulic power
Maintenance on load control valves
Maintenance on hydraulic cylindersNote: For information regarding machine operation without hydraulic power, refer to Operation and Maintenance Manual, SEBU7017 and SEBU7111, "Boom Retracting and Boom Lowering without Hydraulic Power".This procedure should be used for the following cylinders:
Telescoping Cylinder
Boom Cylinder (Boom Raise/Lower)
Stabilizer Cylinder (if equipped)
Frame Leveling Cylinder (if equipped)
Illustration 6 g00747777
Load Control Valve (1) Counterbalance valve (2) Locknut (3) Adjusting screw
Hold adjusting screw (3) in place with a 5/16 inch allen wrench while you use a 9/16 inch spanner wrench with an open end to remove locknut (2). Keep the locknut for reassembly later.
Turn the adjusting screw