EXTENSION 1U7156 - Caterpillar

The V-belt must be tensioned correctly. Failure to tension the belt properly could cause damage to the belt and/or to the air conditioner compressor.
Illustration 1 g00102670Your engine can be equipped with a water pump, with a fan drive, and with an alternator. Your engine can also be equipped with accessory drive belts. For maximum engine performance and maximum utilization of your engine, inspect the belts for wear and for cracking. Check the belt tension. Adjust the belt tension in order to minimize belt slippage. Belt slippage will decrease the belt life. Belt slippage will also cause poor performance of the alternator and of any driven equipment.If new belts are installed, recheck the belt adjustment after 30 minutes of operation. If two belts or more are required for an application, replace the belts in belt sets. If only one belt of a pair is replaced, the new belt will carry more load. This is due to the fact that the older belts are stretched. The additional load on the new belt could cause the new belt to break.Water Pump Belt, Fan Drive Belt, and Alternator Belt
Illustration 2 g00418343
(1) Alternator mounting bolt
(2) Nut
(3) Adjusting bolt
Open the engine hood.
Apply approximately 98 N (22 lb) of force midway between the pulleys.
Measure the deflection of the belt. The belt should deflect 8 to 11 mm (5/16 to 7/16 inch).
If the deflection is not correct, loosen alternator mounting bolt (1) and nut (2). Turn adjusting bolt (3) in order to adjust the belt tension.
When the adjustment is correct, tighten bolt (1) to a torque of 21 4 N m (15 3 lb ft). Tighten nut (2) to a torque of 41 8 N m (30 6 lb ft).
Check the deflection of the belt again. Note: If a new belt is installed, check the belt adjustment again after 30 minutes of engine operation at the rated engine speed.Air Conditioner Belt
Illustration 3 g00418344
(4) Collar
(5) Adjusting bolt
Apply approximately 98 N (22 lb) of force midway between the pulleys.
Measure the deflection of the belt. The belt should deflect 7 to 10 mm (1/4 to 3/8 inch).
If the deflection is not correct, loosen collar (4). Turn adjusting bolt (5) in order to adjust the belt tension.
When the adjustment is correct, tighten collar (4) to a torque of 100 20 N m (75 15 lb ft).
Check the deflection again. Note: If a new belt is installed, recheck the belt adjustment again after 30 minutes of operation.
Close the engine hood.