Hydraulic oil pressure can remain in the hydraulic oil system on this machine after the engine and pump have been stopped. Personal injury can be caused if this pressure is not released before any service is done on the hydraulic systems. To prevent personal injury, refer to the procedure in Testing and Adjusting Manual, "Release of Pressure in the Hydraulic System".
When possible, the bucket must always be lowered to the ground with the cutting edge rotated to the ground before service is started. When it is necessary for the boom to be in the raised position while tests or adjustments are done, be sure that the boom, stick and bucket have correct support.
Be sure the swing parking brakes and the travel parking brakes are on and the brake release lines are disconnected and plugged.
Always move the machine to a location away from the travel of other machines. Be sure that other personnel are not near the machine when the engine is running and tests or adjustments are being made.
Before the pilot oil filter for the hydraulic system can be replaced, the pressure in the hydraulic system must be released.
- Fully retract the rod in the stick cylinder.
Hot oil and hot components can cause personal injury. Do not allow hot oil or hot components to contact the skin.
- Adjust the position of the bucket as the boom is lowered. The bucket must rest flat on the ground.
- Lower the boom until the bucket is flat on the ground.
- Shut off the engine.
- Check the pilot pressure at the pressure tap (1) for the low pressure pilot circuit on the pilot manifold under the cab. If the pressure is below 3000 kPa (435 psi) connect an auxiliary pump unit to this port and pump the pilot pressure to 4000 kPa (580 psi).
(1) Pressure tap for low pressure pilot circuit
- Put the hydraulic activation control lever in the UNLOCK position. Turn the engine start key to the ON position. Do not start the engine.
- Move the control levers for the boom, the stick, the bucket and swing to each of the FULL STROKE positions. Actuate both the trigger switches for the front shovel bucket bottom dump controls. This should release any pressure that might be present in the main implement system. Disconnect the auxiliary pump unit (if used) and install the pressure gauge at the test port. Continue to move the control levers until the pilot system pressure is released. Use a pressure gauge to verify that the pilot system pressure is released.
- Press the button (2) on the hydraulic tank breaker relief valve in order to release the hydraulic tank pressure. The hydraulic tank breaker relief valve is located on the hydraulic tank by the filler pipe.
Hydraulic oil tank for 4CS1-147
Hydraulic oil tank for 4CS148-UP
- The pressure in the system has been released and the pilot oil filter can be replaced.
- Open the hydraulic pump compartment door on the first level of the operator's platform. For more information, refer to Operation and Maintenance Manual, "Access Doors and Covers".
- Use a strap type wrench in order to remove pilot oil filter (3) .
- Inspect the oil filter. Refer to Operation and Maintenance Manual, "Oil Filter - Inspect" for information on inspecting the oil filter.
- Clean the filter housing base. Make sure that all of the old filter seal is removed.
- Lubricate the seal of the new filter with a light coat of hydraulic oil.
- Install the new filter by hand. Additionally tighten the filter by 3/4 turn after the seal contacts the filter base.
- Close the pump compartment door.