PIN AS 8W8454 - Caterpillar

Inspection
Belt tension should be checked initially between the first 20 to 40 hours of engine operation.After the initial check, the belt tension should be checked at Every 250 Service Hours or Three Months.To maximize the engine performance, inspect the belts for wear and for cracking. Replace belts that are worn or damaged.For applications that require multiple drive belts, replace the belts in matched sets. Replacing only one belt of a matched set will cause the new belt to carry more load because the older belt is stretched. The additional load on the new belt could cause the new belt to break.If the belts are too loose, vibration causes unnecessary wear on the belts and pulleys. Loose belts may slip enough to cause overheating.To check the belt tension, apply 110 N (25 lb) of force midway between the pulleys. A correctly adjusted belt will deflect 13 to 19 mm (0.50 to 0.75 inch).Adjustment
Illustration 1 g00797159
Typical illustration (1) Adjusting nuts (2) Mounting bolts
Loosen mounting bolts (2) and adjusting bolt (1) .
Move the alternator in order to increase or decrease the belt tension.
Tighten adjusting bolt (1). Tighten mounting bolts (2). Refer to the Service Manual for the proper torques.If new belts are installed, check the belt tension again after 20 hours of engine operation.Replacement
Refer to the Service Manual for more information on the procedures for the following topics: belt removal and belt installation procedure.