SENSOR-TEMPERATURE 4238351 - Caterpillar

the pressure in the implement hydraulic circuits (boom, stick and bucket) before any hydraulic lines or components are disconnected or removed.
Fully retract the cylinder rod into the stick cylinder.
Adjust the position of the bucket so that the bucket is parallel to the ground.
Lower the boom until the bucket is flat on the ground.
Shut off the engine.
Place the engine start switch to the ON position.
Place the hydraulic activation control lever in the UNLOCKED position.
Move the implement control levers in all directions in order to relieve any pressure that might be present in the pilot system.
Place the engine start switch in the OFF position.
Slowly loosen the fill/vent plug on the hydraulic tank and release the pressure.
Tighten the fill/vent plug on the hydraulic tank to the specified torque.The pressure in the system should now be released and lines and components can be removed.Note: The lines to the boom cylinder may still be pressurized if the machine is equipped with a boom lowering control valve. There is a bleeder valve that is located at the boom cylinder that can be opened in order to relieve any oil pressure that may remain in the system.