Early-model vehicles use multiple belts to operate accessories, where late-model vehicles use a singular serpentine belt with one tensioning point. Early models need to have the correct tension to prevent wear on the belt and slipping. A belt adjusted too tight can cause accelerated bearing wear on the accessories. The majority of the serpentine belt vehicles use a spring-loaded belt tensioner, which maintains the correct tension.
Loosen the tensioner on a serpentine belt by inserting either the ½-inch or 3/8-inch drive ratchet into the opening in the tensioner's arm and moving the tensioner away from the belt. While reducing the tension on the belt, remove it from one of the pulleys. The tensioner can now be released and the belt can be removed.
Map the direction of the serpentine belt installation. They can be confusing since the belt can be installed in several ways on many vehicles, although it will only work one way. Check for a diagram under the hood. Many vehicles have a diagram of the serpentine belt installation. If this is not available, draw a diagram for reference.
Loosen the tensioner on those vehicles that use an accessory or separate manually adjusted tensioner pulley. The vehicles, such as a Jeep, use a tensioning bolt arrangement to tighten the pulley or accessory. This is a small metal plate with a threaded hole in the center. This plate is attached to the tensioner. A long bolt is threaded through the plate and contacts another flat plate, which is in a fixed position. When the bolt is turned clockwise, it pushes on the plate, which causes the threaded plate attached to tensioner to move outward, increasing tension. When the bolt is turned outward or counter-clockwise, the tension is removed.
Wrap the serpentine belt over all the pulleys except one. Install the belt over the tensioner, but keep the belt clear of the easiest pulley to install the belt when the tensioner is moved to reduce the tension. Hold the loose end of the belt and slide it over the last pulley as the tensioner is moved away from the belt.
Remove the V belt on early-model vehicles by loosening the two bolts securing the alternator to the support bracket. This will allow the alternator to move inward, reducing the tension so the belt can be removed. Some foreign vehicles use a separate tensioner bolt attached to the alternator to apply tension. Loosen the horizontal bolt on the side of the bracket this bolt is attached to and then turn the bolt counter-clockwise to loosen the tension. The opposite is true to apply tension to the belt.
