SUPPORT-TRUNNION 3559708 - Caterpillar

Release Procedure
Personal injury can result from hydraulic oil pressure and hot oil.Hydraulic oil pressure can remain in the hydraulic system after the engine has been stopped. Serious injury can be caused if this pressure is not released before any service is done on the hydraulic system.Make sure all of the work tools have been lowered to the ground, and the oil is cool before removing any components or lines. Remove the oil filler cap only when the engine is stopped, and the filler cap is cool enough to touch with your bare hand.
Note: Make sure that the parking brake is engaged.
Position the bucket so that the cutting edge is pointing downward by approximately 20 degrees.
Lower the bucket until the bucket teeth are barely off the ground. This ensures that the head end of the lift cylinder is pressurized. Oil from the lift cylinder is used as the pilot supply oil for a dead engine.
Turn the engine start switch to the OFF position.
When the engine has stopped, turn the engine start switch back to the ON position so that pilot oil can reach the main valves.
Move the implement lockout switch to the UNLOCKED position.
Move the lift control lever to the FLOAT position and the tilt control lever to the TILT BACK position at the same time. This allows the bucket to tilt back while the boom is lowered.The bottom of the bucket should rest flat on the ground and the weight of the linkage should be supported by the ground. The pressure from the head end of the lift cylinder and from the ride control accumulators is now vented to the hydraulic tank.
When the bucket has settled to the ground, move both control levers to the HOLD position. Then, cycle the control levers through all positions in order to purge any remaining pressure from the implement hydraulic system.
Move the STIC steering and transmission lock control to the UNLOCKED position.
Move the STIC steering control lever to the left and to the right. This will release any pressure in the steering system.
Depress the brake pedal repeatedly. This will release any pressure in the braking system.
Turn the engine start switch to the OFF position.
Slowly loosen the hydraulic tank filler cap on the left side of the machine. This will release the pressure in the tank.
After all of the pressure has been released, tighten the hydraulic tank filler cap.Note: The hydraulic system pressure in the brake system and the steering system has now been released. Hydraulic lines and components can now be removed.