If the pulleys are not properly aligned, excessive belt wear will occur. It may cause fan vibration, and could cause the belt to “jump” off of the pulleys. The pulley alignment should be accomplished by laying a level or straight edge across the pulleys. Both pulleys should be level and aligned. If not:

• Remove the belt (see How to replace a belt).
• Loosen the driven pulley (shaft pulley), and adjust up and down to obtain level.
• Firmly re-tighten the pulley
• Re-install and re-adjust the belt.