Most automobiles use an idler pulley to maintain pressure on the drive belt. Over time, the belt stretches and the idler pulley runs out of travel and no longer maintains proper tension on the drive belt. Conventional wisdom dictates you should change the drive belt. However, if the drive belt does not show signs of cracking or dry rot, you can tighten the belt by adjusting the alternator and get more miles out of that old belt.
Loosen the alternator through the bolt located on top of the alternator and loosen the alternator pivot bolt located on the bottom of the alternator using a socket and ratchet.
Place a pry bar between the mounting bracket for the alternator and the bottom casing of the alternator.
Push down on the handle of the pry bar and raise the level of the alternator approximately one inch.
Tighten the through bolt and pivot bolt using the socket while you maintain downward pressure on the pry bar. This pulls the idler pulley upward and creates more pressure on the drive belt.
