904B Compact Wheel Loader Caterpillar

The machine should be on level ground. Lower the bucket to the ground and apply slight downward pressure. Engage the parking brake and stop the engine.

Illustration 1	g01144677

1. Remove the hydraulic tank filler cap (1).

2. The hydraulic tank drain plug (2) is located on the bottom of the hydraulic tank on the underside of the machine. Remove the drain plug and allow the hydraulic oil to drain into a suitable container.

3. Install the drain plug.

4. Change the hydraulic system filter. Refer to Operation and Maintenance Manual, "Hydraulic System Oil Filter (Return) - Change".

5. Fill the hydraulic system oil tank with hydraulic oil. Refer to Operation and Maintenance Manual, "Lubricant Viscosities" and Operation and Maintenance Manual, "Refill Capacities".

   Note: Observe the sight gauge for the hydraulic oil level as you fill the hydraulic system oil tank. Do not overfill the tank.

6. Inspect the gasket on the hydraulic tank filler cap for damage. Replace the gasket, if necessary.

7. Install the hydraulic tank filler cap.

8. The sight gauge for the hydraulic oil level (3) is located on the right side of the tank. Maintain the hydraulic oil level in the center of the sight gauge. Add oil, if necessary.

   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.