M11 Series – Service Manual – 013-005   Drive Belt, Alternator

Insert a 3/8-inch breaker bar into the space provided on the tensioner.

Rotate the tensioner away from the belt until it stops.

Remove the alternator belt while holding the tensioner back.

Loosen the adjusting screw locknut (1).

Loosen the adjustment link locking capscrew (2).

Loosen the alternator mounting capscrew (3).

Turn the adjusting screw (4) counterclockwise to release tension.

Remove the alternator belt.

Install a new belt over the pulleys while holding the tensioner back. Make sure not to damage the belt while working it over the flanged pulleys.

Release the tensioner, and remove the breaker bar.

Belt drive systems equipped with an automatic belt tensioner can not be adjusted. A belt tension gauge will not give an accurate measure of the belt tension. The automatic belt tensioner is designed to maintain proper belt tension over the life of the belt. Only inspection of the tensioner is required.

The belt tensioner is designed to operate within the limit of arm movement provided by the cast stops when the belt length and geometry are correct.

If the tensioner is hitting either of the limits during operation, check the mounting brackets and the belt length. Loose brackets, bracket failure, alternator movement, incorrect belt length, or belt failure can cause the tensioner to hit the limits.

NOTE: A belt is considered used, if it has been in operation for 10 minutes or longer.

Install a new belt on the water pump and alternator pulleys. To prevent damage, do not roll a belt over the pulley or pry it on with a tool.

Turn the adjusting screw (1) clockwise to increase the belt tension.

Use belt tension gauge, Part Number ST-1293, or equivalent, to measure the belt tension. Refer to Procedure 018-005 for the correct tension.

Tighten the adjusting screw locknut (2) against the retainer.

Tighten the adjustment link locking capscrew (3).

Tighten the pivot capscrew (4) and nut (5).

Belts must not touch the bottom of the pulley grooves, or protrude over 3 mm [3/32 in] above the top edge of the groove.

NOTE: If the engine is equipped with a secondary alternator, reference the vehicle manufacturer for the secondary alternator belt adjustment procedure.

Belt drive systems equipped with an automatic belt tensioner can not be adjusted. A belt tension gauge will not give an accurate measure of the belt tension. The automatic belt tensioner is designed to maintain proper belt tension over the life of the belt. Only inspection of the tensioner is required.

The belt tensioner is designed to operate within the limit of arm movement provided by the cast stops when the belt length and geometry are correct.

If the tensioner is hitting either of the limits during operation, check the mounting brackets and the belt length. Loose brackets, bracket failure, alternator movement, incorrect belt length, or belt failure can cause the tensioner to hit the limits.

Loosen the adjusting screw locknut (1).

Loosen the adjustment link locking capscrew (2).

Loosen the pivot capscrew and nut (3).

NOTE: A belt is considered used if it has been in operation for 10 minutes or longer.

Use belt tension gauge, Part Number ST-1293, or equivalent, to measure belt tension.

Turn the alternator adjusting screw (1) clockwise to tighten the belt. Refer to Procedure 018-005 for the correct belt tension.

Tighten the adjusting screw locknut (2) against the retainer.

Tighten the adjustment link locking capscrew (3).

Tighten the pivot capscrew (4) and nut (5).