J621 TRACTOR-SCRAPER Every 2000 Service Hours or 1 Year Caterpillar

Every 2000 Service Hours or 1 Year
1.1. (34)Steering Column Shaft Upper Bearing
2.1. (35)Seat Suspension
3.1. (36)Tractor Brake Camshaft Bearings
4.1. (37)Scraper Brake Camshaft Inner And Outer Bearings
5.1. (38)Ejector Carrier Roller Bearings
6.1. (39)Hydraulic System
7.1. (40)Differential And Final Drives
8.1. (41)Speed Reducer
9.1. (42)Diesel Engine Valve Lash

(34)Steering Column Shaft Upper Bearing

Lubricate 1 fitting.

(35)Seat Suspension

Lubricate 3 fittings.

(36)Tractor Brake Camshaft Bearings

Lubricate 1 fitting by each wheel.

(37)Scraper Brake Camshaft Inner And Outer Bearings

Lubricate 2 fittings by each wheel (2 strokes each).

(38)Ejector Carrier Roller Bearings

1. Raise ejector and block to remove weight from carrier roller.

2. Remove cover.

3. Remove cotter pin, nut and washer.

4. Remove carrier roller. Wash shaft and carrier parts in clean solvent. Inspect parts for wear.

5. Apply grease to inner bearing. Install carrier roller and fill with grease.

6. Install outer bearing, washer and nut.

7. Tighten nut until roller locks. Back off 1/6 turn. (Roller must turn freely by hand.)

8. Install cotter pin, pack in grease and install cover.
9. Remove jack and blocking.
10. Repeat procedure for other carrier roller.
11. See item 46 for roller adjustment.

(39)Hydraulic System

1. When oil is warm, lower bowl, close floor and retract ejector. Stop the engine. Move all scraper controls to relieve pressure.

2. Remove filler cap slowly to relieve pressure.

3. Remove hydraulic tank drain plug.

4. Open drain valve and drain oil.
5. Change filter elements. (See item 27.)
6. Close drain valve.
7. Clean and install drain plug.

8. Remove snap ring and filler strainer. Wash strainer in clean solvent. Install strainer.

9. Fill hydraulic tank to bottom of filler strainer. (See Refill Capacities.)

10. Start engine and run at low idle with controls in HOLD position.

11. Fill tank to FULL mark in sight gauge and install filler cap.
12. Bleed filter elements. (See Item 27.)

(40)Differential And Final Drives

1. Position final drive drain plugs down.

2. Remove final drive drain plugs.

3. Remove differential drain plug. Clean and install drain plugs.

4. Remove final drive fill plugs.

5. Fill final drives to level of fill plug openings. Clean and install fill plugs.

6. Remove differential fill cap. Fill differential to FULL mark on plunger gauge. (See Refill Capacities.

7. Clean and install fill cap.
8. Wash breather. (See item 31.)
9. Start engine and operate tractor-scraper on level ground a few minutes.

10. Check oil level. Oil should be to FULL mark on plunger gauge. Add oil if necessary.

(41)Speed Reducer

1. Park tractor-scraper on level ground. Stop engine. Remove drain plugs.

2. Clean and install drain plugs.

3. Remove level and fill plugs. Fill reducer to bottom of level plug opening. Clean and install level and fill plugs.

(42)Diesel Engine Valve Lash

Valve Numbering Guide

1. Adjust valves with engine stopped.

2. Remove camshaft covers.

3. Remove timing bolt and inspection cover.

4. Turn flywheel on crankshaft in the direction of normal engine rotation until timing mark becomes visible.
5. Remove dowels from storage holes from both banks.

6. Install dowels in timing holes one in each bank.
7. Continue to turn the crankshaft slowly until dowels drop into matching holes in the camshafts as the timing mark becomes aligned. If both don't drop see your AVSpare dealer.

8. Timing mark "TC1-7" on the flywheel will be directly beneath "TC1-7" timing hole in flywheel housing. Install timing bolt.
9. The valves for No. 1 cylinder are closed at this point.

10. Adjust lash for No. 1, No. 4, No. 5 and No. 8 exhaust valves.

11. Turn adjusting screw clockwise to obtain zero lash. There should be no free rocker movement or adjusting screw button lateral movement.


The adjusting screw button can still be rotated by finger pressure even when it is in contact with valve stem and clearance is zero. Turning the adjusting screw clockwise beyond this point will force the valve off its seat, and final lash setting will be incorrect.

12. Turn adjusting screw counterclockwise specified number of clicks on detent. (See page 23.)

13. Adjust lash for No. 1, No. 3, No. 6 and No. 8 inlet valves.

14. Remove timing bolt.

15. Remove dowels from timing holes and insert in storage holes.

16. Turn flywheel 360° and align flywheel timing mark "TC1-7" with the timing pointer.

17. Install timing bolt in flywheel.

NOTE: The camshaft will rotate only 180° during 360° crankshaft rotation. The camshaft timing mark should not be visible at this time.

18. The valves for the No. 7 cylinder are closed at this point.

19. Adjust lash for No. 2, No. 3, No. 6 and No. 7 exhaust valves.

20. Adjust lash for No. 2, No. 4, No. 5 and No. 7 inlet valves.
21. Remove bolt from flywheel.
22. Install inspection cover.
23. Install camshaft covers.