This article mainly introduces Caterpillar 426 Hydraulic System Oil-Change
Operate the machine for a few minutes in order to warm the hydraulic system oil.
The machine should be level.Lower the bucket to the ground and apply slight downward pressure.
Engage the parking brake and stop the engine.
The hydraulic tank filler cap is located under the access door on the top of the engine compartment.
1. Pull the hood release lever(1) in order to open the engine access door (2) on the top of the machine.
2.Remove the hydraulic tank fller cap.
3. Remove the drain plug on the flange that is located on the hydraulic pump. Allow the oil to drain into a suitable container.
4. Clean the drain plug and replace the drain plug.
Tighten the drain plug to a torque of 90±10N-m
(66±7Ib ft).
5. Change the hydraulic system filter. Refer to Operation and Maintenance Manual,"Hydraulic System Oil Filter-Change".
6. Inspect the hydraulic tank breather that is located on a hose from the overflow container.
Replace the breather, if necessary.
7. Fill the hydraulic system oil tank. Refer to Operation and Maintenance Manual,"Lubricant Viscosities"and Operation and Maintenance Manual,"Refill Capacities".
8. Maintain the hydraulic oil level in the sight gauge between the "MIN"mark and the "MAX"mark.
Check the hydraulic oil level with the loader onthe ground and with the backhoe in the transport position.
Note: The oil must be free of bubbles. If bubbles are present in the oil, air is entering the hydraulic system. Inspect the suction hoses and hose clamps.
9. Inspect the gasket on the hydraulic tank filler cap for damage. Replace the gasket, if necessary.
10. Install the hydraulic tank filler cap.
11. Close the access door.
