See Figures 1, 2, 3 and 4
Check the condition of the drive belts and check the belt tension at least every 15,000 miles (24,000 km).
- Inspect the belts for signs of glazing or cracking. A glazed belt will be perfectly smooth from slippage, while a good belt will have a slight fabric texture visible. Cracks will generally start at the inner edge of the belt and run outward. Replace the belt at the first sign of cracking or if the glazing is severe.
- Belt tension does refer to play or droop. By placing your thumb midway between the two pulleys, it should be possible to depress the belt 1 / 4 - 1 / 2 inches (6-12mm). If any of the belts can be depressed more than this, or cannot be depressed this much, adjust the tension. Inadequate tension will always result in slippage or wear, while excessive tension will damage pulley bearings and cause belts to fray and crack.
- Its not a bad idea to replace all drive belts at 60,000 miles (96,000 km) regardless of their condition.
See Figures 5 through 14Alternator
To adjust the tension of the alternator drive belt, loosen the pivot and mounting bolts on the alternator. Using a wooden hammer handle or a broomstick, or even your hand if you're strong enough, move the alternator one way or the other until the tension is within acceptable limits.
Tighten the mounting bolts securely. If a new belt has been installed, always recheck the tension after a few hundred miles of driving.
A/C compressor belt tension can be adjusted by turning the tension adjusting bolt which is located on the compressor tensioner bracket. Turn the bolt clockwise to tighten the belt and counterclockwise to loosen it.Air Pump
To adjust the tension of the air pump drive belt, loosen the adjusting lever bolt and then the pivot bolt. Move the pump in or out until the desired tension is achieved.
The tension should always be checked between the air pump and the crankshaft pulley on all trucks without air conditioning. On trucks with air conditioning, tension should be checked between the A/C compressor and the crankshaft pulley.Power Steering Pump
Tension on the power steering belt is adjusted by means of an idler pulley. Turn the adjusting bolt on the idler pulley until the desired tension is achieved and the retighten the idler pulley lockbolt.