769D Off-Highway Truck and 771D Quarry Truck Caterpillar

1. Push the button on the breaker relief valve. The breaker relief valve is located on top of the steering hydraulic tank.

2. Slowly, remove the filler cap on the steering hydraulic tank in order to relieve the pressure. Install the filler cap after the tank has been drained. This will prevent dirt from entering the system.
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   NOTICE
   Care must be taken to ensure that fluids are contained during performance of inspection, maintenance, testing, adjusting and repair of the product. Be prepared to collect the fluid with suitable containers before opening any compartment or disassembling any component containing fluids. Refer to Special Publication, NENG2500, "Caterpillar Dealer Service Tool Catalog" for tools and supplies suitable to collect and contain fluids on Caterpillar products. Dispose of all fluids according to local regulations and mandates.

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   Illustration 1	g00514254

3. Attach a quick connecting hose to the drain valve on the steering hydraulic tank.

4. Open the drain valve.

5. Drain the oil into a suitable container. Close the drain valve and remove the quick connecting hose.

Wash the Cap and the Filler Screen

1. Remove the tank filler cap.

2. Remove the retaining ring on the screen.

3. Remove the filler screen. Wash the cap and the screen in clean, nonflammable solvent. Allow the cap and the screen to dry.

4. Inspect the cap seal. Use a new seal if the used seal is damaged.

5. Install the screen, the retaining ring and the cap.

Filling the Steering Hydraulic System

1. Fill the steering hydraulic tank. Refer to Operation and Maintenance Manual, "Lubricant Viscosities". Refer to Operation and Maintenance Manual, "Capacities (Refill)".
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   Illustration 2	g00518509

2. When the engine is not running, the oil level should be at the "FULL COLD" mark in the sight glass.

3. Add oil to the steering hydraulic tank in order to raise the oil level to the safe starting range.

4. Start the engine and run the engine for approximately 15 seconds. The oil level will decrease as oil fills the system.

5. Stop the engine.

6. Check the oil level in the tank. Fill the tank to the "FULL COLD" mark in sight glass (1).

7. Start the engine. Operate the machine in order to warm the oil. Stop the machine. Observe the oil level and inspect the machine for leaks. If necessary, add oil. Make any necessary repairs.

8. Maintain the oil level to the "FULL WARM" mark in the sight glass. Install the filler cap.