Checking and adjusting the Fan Drive Belt

Check the belt tension. When the belt is correctly tensioned it should be possible to depress the belt 10mm at point ‘C’ (centre between the two pulleys) by applying a 10Kg load. (firm push)

If it is more than 10mm the belt could be slipping causing the dynamo or alternator not to work effectively.

If it is too tight, that entire extra load is put onto the bearings, which will gradually ruin the bearings.

To adjust the tension, proceed as follows:

Remove the three 10mm nuts (D).

Withdraw the outer pulley half.

Note. If the belt has any wear or is splitting, fit a new belt

To tighten the belt, remove one or more of the large shim washers.

To slacken the belt, add one or more shim washers.

The shim washers that have been removed should be refitted on the outer side of the pulley. Always fit the thick shim washer under the spring washers and nuts.


Fitting a new belt

  1. With the front pulley and large shims removed and the back part of the fan pulley in place.
  2. Put the fan belt over the crankshaft pulley and pull and see whereabouts it is situated on the fan pulley, if it is low down in the pulley, put all the washers between the two pulley half’s. If it is halfway up the pulley, only half the washers are on the inside and the rest outside.
  3. Once you have determined roughly the amount of washers (you should have one thick, a number of medium thickness and one thin shim washer) On the first setting use the thick shim washer on the inside.
  4. Fit the “spare” washers out-side the pulley and fit the nuts without spring washers and start to tighten.
  5. NOW BE CAREFUL YOU WILL TRAP THE BELT AT THE SMALLEST DIAMETER. Turn the engine over by hand and the belt will start to ride out of the small diameter into its correct seating position.
  6. When the bolts are tight now check the belt tension. If it is too tight, you will have to remove the three nuts and half the pulley, and add a thinner washer between the two pulley half’s and try again. You may have to do it a couple of times before you get it right.
  7. Once the belt tension is correct take one nut off and fit the spring washer then do the rest one at a time.
  8. Start the car and run for a couple of minutes. Stop the engine and recheck the belt tension.