KIT (Spider & Bearing) 8D2909 - Caterpillar

Inspection
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 accurately check the belt tension, a suitable gauge should be used. Refer to the Disassembly and Assembly manual for the correct procedure. If a suitable gauge is not available, apply 45 N (10 lb ft) of force midway between the pulleys. A correctly adjusted belt will deflect 10 mm (0.39 inch).Adjustment
Illustration 1 g00994667
Typical example
(1) Adjusting bolts
(2) Mounting bolts
Loosen the mounting bolts (2) and the adjusting bolts (1).
Move the alternator in order to increase or decrease the belt tension.
Tighten the adjusting bolts (1). Tighten the mounting bolts (2). Refer to the Specifications Manual for the correct torque settings. Replacement
Refer to the Disassembly and Assembly manual for the installation procedure and the removal procedure for the belts.