621 TRACTOR-SCRAPER Every 500 Service Hours Or 3 Months Caterpillar

(19)Hydraulic Control System

Machine level, scraper lowered, parking brake set and engine stopped.

Move hydraulic controls to help relieve hydraulic pressure.

Remove tank filler cap slowly to relieve pressure.

Non-Cushion Hitch

1. Loosen filter cover bolt and remove cover and element assembly.

Cushion Hitch

1. Remove filter cover bolts and install 3 bolts in puller holes. Pull cover by turning bolts in evenly to prevent binding.

2. Remove filter elements and screen.

3. Wash screen and cover with clean solvent.

4. Blow or shake dry.

Show/hide table

When using pressure air wear safety glasses and protective clothing. Maximum air pressure must be below 30 PSI (2 kg/cm2).

5. Install screen and new elements.

6. Inspect cover seal. Use new one if necessary. Apply a coat of clean oil to cover seal.

7. On non-cushion hitch install cover assembly and tighten cover bolt to 43 ± 4 lb. ft. (5.9 ± 0.6 mkg).

7. On cushion hitch install cover carefully to avoid damage to seal. Install bolts and tighten bolts evenly.

8. Install tank cap.

9. Check oil level and add oil if necessary.

10. Start engine and check for leaks.

(20)Transmission System

1. Remove filter housing drain plug.

2. Remove cover and element. Clean housing.

3. Remove element from cover. Inspect seals. Install new seals if necessary.

4. Install new element. Tighten to 10 ± 2 lb. ft. (1.5 ± 0.3 mkg).

5. Install cover.

6. Clean and install filter housing drain plug. Tighten to 35 ± 5 lb. ft. (4,8 ± 0,7 mkg).

7. Remove magnetic strainer drain plug.

8. Remove cover.

9. Remove screen and magnets.

10. Remove magnets from screen and wash both in clean solvent.

11. Clean magnets with a soft cloth, stiff brush or compressed air.

Show/hide table

When using pressure air wear safety glasses and protective clothing.

12. Install screen and magnets as a unit with small end of tube out. Be sure screen is piloted on the tube.

13. Check cover seals. Install new seals if necessary.

14. Install cover.

15. Clean and install drain plug.

16. Start engine and operate machine a few minutes.

17. Check oil level with oil warm and engine running at low idle. Maintain oil level to FULL mark on dipstick.

(21)Ejector Support Rollers

Lubricate 2 bearing rollers on each side. Total of 4 fittings.

(22)Diesel Engine Crankcase

1. Loosen hose clamp. Remove cover assembly, elements and housing.

2. Wash elements and housing in clean solvent and dry.

3. Install housing, elements and cover assembly. Tighten hose clamp.