V-Belt Failures And Engine Component Failures Due To Incorrect Belt Tension Caterpillar

Problem:

Reports have been received of V-Belt failures and engine component failures as a result of incorrect belt tension. The reports have included failure of water pump bearings, water pump, alternator, and brackets due to over-tightened belts.

Solution:

Inspect the condition of the 7N-0510 V-Belt after every 50 service hours. V-Belts that are worn or damaged should be replaced. (a) (b)

Check the adjustment of the 7N-0510 V-Belt. Use one of the following methods to check for correct adjustment.

(a) Belt Deflection Check - The 7N-0510 V-Belt should deflect 10 mm (0.4 inch) under a straight pull of 44 N (10 lb). This measurement should be taken between the alternator pulley and the crankshaft pulley.

(b) Tension Gauge Check - The tension of the 7N-0510 V-Belt should be 445 +/- 22 N (100 +/- 5 lb) for a new belt and 400 +/- 22 N (90 +/- 5 lb) for a used belt. A used belt refers to a belt that has been in operation for 30 minutes or more. This measurement should be taken between the alternator pulley and the crankshaft pulley.

Adjust the alternator as necessary in order to obtain the correct tension as specified above. Refer to "Adjusting the Belt Tension" in the Operation and Maintenance Manual for your machine.

NOTE: The recommended method of checking the adjustment of the V-Belt is checking the tension using a Borroughs Belt Tension Gauge. The part number for this gauge is 144-0235. Operating instructions and gauge calibration information are provided with the 144-0235 Belt Tension Gauge.

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