641B & 651B TRACTOR-SCRAPERS Every 250 Service Hours Or Monthly Caterpillar

Every 250 Service Hours Or Monthly
1.1. (15)Engine Crankcase
2.2. Spin-on Type Engine Oil Filters
3.1. (16)Fan Belt
4.1. (17)Tractor And Scraper Brakes

(15)Engine Crankcase

Spin-on Type Engine Oil Filters

NOTE: Engine crankcase oil must be changed at 125 SERVICE HOURS. (See Item 14).

1. Remove used filters. Clean seal contact surface of filter bases. Be sure all of used filter seals are removed.

2. Coat seal of new filter with clean oil.
3. Install new oil filter. When filter seal contacts filter base, tighten an additional 3/4 turn.


Do not overtighten.

4. Start engine and run at low idle to fill filters. Check for leaks.

5. Stop engine. Check oil level. Add oil as necessary.

(16)Fan Belt

1. Check condition and adjustment of belt. Correct adjustment allows 9/16 to 13/16 inch (14 to 20 mm) deflection.

2. To adjust, loosen locknut.

3. Turn adjusting nut to obtain correct deflection.

(17)Tractor And Scraper Brakes

1. Stop engine. Measure distance from rotochamber to slack adjuster clevis pin.

2. Apply brakes and check movement of adjuster at pin. If travel is 3 inches (76 mm) or more, adjust brakes.

3. To adjust, loosen adjustment locking bolt by turning counterclockwise.

4. Turn adjusting bolt in or out as necessary to limit travel to 21/2inches (63,5 mm).

5. Tighten adjustment locking bolt.
6. Apply and release brakes while observing brake assembly.
7. Check for rotochamber rod binding.
8. Check diaphragm for leakage.
9. Repeat procedure for each wheel brake.
10. Start engine. Do not move machine until air pressure is in NORMAL range. Remove blocks and move machine to check for dragging brakes.