621 TRACTOR-SCRAPER Every 250 Service Hours Or Monthly Caterpillar

(13)Steering Follow-Up Linkage

Lubricate 3 fittings. (Non-Cushion-Hitch machines only).

(14)Transmission Control

Effective with Serial Number 23H1 thru 23H3510 lubricate 1 fitting.

(15)Belt Adjusting Pulley

Lubricate 1 fitting.

(16)Fan Bearings

Lubricate 1 fitting.

(17)Belt Adjustment

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. Tighten locknut.

(18)Brake Adjustment

1. With brakes released, check distance from rotochamber to slack adjuster arm.

2. Depress brake pedal and check movement of arm. If movement is more than 3 inches (75 mm) for tractor brakes and more than 21/2 inches (60 mm) for scraper brakes, adjust brakes.

3. To adjust, turn locking bolt 1/2 turn counterclockwise.

4. Turn adjusting nut in or out to limit movement to 1-5/8inches (40 mm) for the tractor brakes and 1-1/4 inches (32 mm) for the scraper brakes.

5. Turn locking bolt 1/2 turn clockwise.

6. Check rod movement for binding. Check diaphram for air leaks. Check for dragging brakes.