631E Series II Wheel Tractor-Scrapers Caterpillar

Illustration 1	g00441328

The hydraulic tank breaker relief valve is located on the top of the hydraulic tank near the hydraulic oil filter cover. The relief valve controls the pressure in the tank. The relief valve controls the vacuum in the tank.

1. Clean the debris from the relief valve (1).

2. Turn the relief valve counterclockwise in order to remove the relief valve. Remove the relief valve slowly in order to relieve the pressure that is in the tank.

3. Remove the retaining ring from the top of the relief valve.

4. Remove the metal cover that is under the retaining ring. A filter is under the metal cover.

5. Wash the breaker relief valve in a clean nonflammable solvent. Wash the filter in a clean nonflammable solvent.

6. Dry the relief valve. Dry the filter. Use compressed air in order to speed the drying.

7. Inspect the filter for damage. Replace the filter if the filter is damaged.

8. Inspect the O-rings that are between the filter and the housing of the relief valve. Replace the O-rings if the O-rings are damaged.

9. Inspect the relief valve for damage. Replace the relief valve if the relief valve is damaged.

10. Apply a light coat of oil to the O-rings. Assemble the filter on the relief valve.

11. Install the relief valve on the hydraulic tank.