D3C Series III, D4C Series III and D5C Series III HYSTAT Track-Type Tractors Hydraulic System Oil - Change Caterpillar

Operate the machine for a few minutes in order to warm the hydraulic system oil.

Park the machine on level ground. Lower all attachment to the ground. Move the transmission lock lever to the LOCKED position. Stop the engine.

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1. Remove the hydraulic tank filler cap that is located on the rear of the machine.

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2. Remove the drain plug on the hydraulic oil tank drain valve. Installation of 7B-7908 Pipe Nipple is required in order to drain the hydraulic oil from the hydraulic oil tank. Allow the hydraulic oil to drain into a suitable container.

3. Remove the pipe nipple and install the drain plug.

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4. Open the access door on the rear of the machine.

5. Change the hydraulic system filter. Refer to Operation and Maintenance Manual, "Hydraulic System Oil Filter - Change" .

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6. Remove the access panel on the right side of the machine.

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7. Remove the hydraulic tank breather.

8. Clean the hydraulic tank breather with a nonflammable solvent and allow the hydraulic tank breather to dry.

9. Replace the hydraulic tank breather.

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

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

12. Install the hydraulic tank filler cap.

13. Start the engine and run the engine for a few minutes.

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14. Maintain the hydraulic oil level above the "ADD" mark on 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 the hose clamps.

15. Stop the engine.

16. If necessary, tighten any loose clamps and any loose connections. Replace any damaged hoses.

17. Close the access door.