980 WHEEL LOADER Every 2000 Service Hours Caterpillar

(34)Hydraulic System

1. Drain system when oil is warm. Raise bucket and tilt it back. Stop engine.

2. Remove filler cap slowly to relieve pressure.

3. Remove drain plug and allow oil to drain.

4. Dump bucket and lower cutting edge onto a 10 inch (0,25 m) block.

5. Move lift control to FLOAT. Hold tilt control in TILT BACK until bucket is completely lowered.

6. Remove oil filler screen.

7. Wash screen in clean kerosene. Install screen.

8. Clean and install drain plug.

9. Install new filter elements. (See item 27)

10. Loosen bleed plug.

11. Fill tank to above ADD mark in sight gauge. (Refill capacity on page 28.)

12. Install fill cap loosely.

13. Start engine and operate at 1/2 engine speed.

14. Tighten bleed plug when oil flows without air bubbles.

15. Raise bucket approximately 4 feet (1,2 m). Dump bucket.

16. Remove filler cap and fill tank to above ADD mark in sight gauge.

17. Install filler cap loosely.

18. Loosen bleed plug. Tighten plug when oil flows without air bubbles.

19. Tilt bucket back. Completely raise, then lower bucket

NOTE: Do not operate over relief valve pressure or allow bucket control to go into FLOAT position.

20. Remove filler cap and fill tank to above ADD mark in sight gauge.

21. Install filler cap tightly. Operate engine at high idle.

22. Completely raise, dump and lower bucket 10 times. Check oil level. Add oil and bleed system as necessary.

(35)Engine Valve Lash

Check valve lash with engine stopped.

1. Remove valve cover.

2. Turn engine to close No. 1 exhaust and inlet valves.

3. Remove plug and install bolt (Part No. L2070) in flywheel.

4. Check valve lash for No. 1, No. 3 and No. 5 exhaust valves. Adjust if necessary. See page 21.

5. Check valve lash for No. 1, No. 2 and No. 4 inlet valves. Adjust if necessary.

6. Remove bolt from flywheel.

7. Turn flywheel 360° to close No. 6 exhaust and inlet valves.

8. Install bolt in flywheel.

9. Check valve lash for No. 2, No. 4 and No. 6 exhaust valves. Adjust if necessary.

10. Check valve lash for No. 3, No. 5 and No. 6 inlet valves. Adjust if necessary.

11. Remove bolt and install plug. Start engine and operate at low idle.

12. Check valve rotators. If valves do not rotate, see your AVSpare dealer.

13. Stop engine and install valve cover. Tighten bolts to 6 to 10 lb. ft. (0,8 to 1,4 mkg) in the above sequence.

Adjusting Valve Lash

1. Loosen locknut and turn adjusting screw.

2. Check adjustment.

3. Tighten locknut and recheck adjustment.