120H Motor Grader Caterpillar

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Hot oil and hot components can cause personal injury. Do not allow hot oil or hot components to contact skin.

Operate the machine until the oil is warm.

Park the machine on a level surface with front wheels straight ahead. Lower all attachments to the ground. Apply a slight downward pressure to the attachments. Center the articulation of the machine and install the frame lock pin. The frame lock pin must move freely in the frame. Move the front wheels to vertical and install the bolt for the wheel lean. Engage the parking brake. Stop the engine.

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The hydraulic system oil tank is positioned behind the operator station at the center of the machine.

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1. Slowly remove the hydraulic oil filler cap.

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2. The drain plug is positioned in the bottom of the hydraulic oil tank. Remove the drain plug. Drain the oil into a suitable container.

   Note: Discard any drained fluids according to local regulations.

3. Replace the filter for the hydraulic system oil. See Operation and Maintenance Manual, "Hydraulic System Oil Filter - Replace" in the Maintenance Interval Schedule.

4. Remove the filler screen from the filler tube in the hydraulic oil tank. Wash the filler screen in clean nonflammable solvent. Allow the filler screen to dry.

5. Clean the drain plug and install the drain plug.

6. Install the filler screen.

7. Fill the hydraulic system oil tank. See Operation and Maintenance Manual, "Refill Capacities".

8. Inspect the filler cap gasket. If the filler cap gasket is damaged, replace the filler cap gasket.

9. Install the hydraulic oil filler cap.

10. Start the engine. Run the engine for a few minutes.

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11. Maintain the oil level above the "ADD" mark in sight gauge (1). If necessary, add oil through the filler tube (2) .

Note: The oil must be free from bubbles. If there are bubbles in the oil, then air is entering the hydraulic system. Inspect the suction hoses and inspect the clamps.

12. Stop the engine.

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