Inspect the belts for signs of glazing or cracking. A glazed belt will be perfectly smooth from slippage, while a good belt will have a slight texture of fabric visible. Cracks will usually start at the inner edge of the belt and run outward. All worn or damaged drive belts should be replaced immediately. It is best to replace all drive belts at one time, as a preventive maintenance measure, during this service operation.
Check the drive belts every 7,500 miles or six months for evidence of wear such as cracking, fraying, and incorrect tension. Determine belt tension at a point halfway between the pulleys by pressing on the belt with moderate thumb pressure. If the distance between the pulleys (measured from the center of each pulley) is 13-16", the belt should deflect 1 / 2 " at the halfway point or 1.4" if the distance is 7-10". If the deflection is found to be too much or too little, loosen the mounting bolts and make the adjustments.
The replacement of the inner belt on multi-belted engines may require the removal of the outer belts.
Before you attempt to adjust any of your engine's belts, you should take an old rag soaked in solvent and clean the mounting bolts of any road grime which has accumulated there. On some of the harder-to-reach belts, especially on late model V8's with air conditioning and power steering, it would be especially helpful to have a variety of socket extensions and universals to get to those hard-to-reach bolts.
When adjusting the air pump belt, if you are using a prybar, make sure that you pry against the cast iron end cover and not against the aluminum housing. Excessive force on the housing itself will damage it.
When replacing a serpentine belt, insert a 1 / 2 in. breaker bar into the slot provided on the self adjusting belt tensioner and pry up enough to slip the belt out from under the pulley. Installation is the reverse of removal. Do not allow the tensioner to "snap" back, release pressure slowly on tensioner.