How to Install a Mustang Belt Tensioner Assembly on your 2003-2004 GT Mustang

1. Remove the belt from your old belt tensioner assembly by inserting the breaker bar into the square hole in the old belt tensioner assembly. 

2. Rotating the breaker bar clockwise to release tension on the belt. While holding the breaker bar at the rotated position, move the old belt tensioner assembly just enough so that the belt can be removed. 

Note, when replacing the belt tensioner, it may be wise to replace the belt. Routine replacement of the belt will ensure that the belt does not fail when the engine is in use. 

3. Next, use the 8mm socket and ratchet or breaker bar to loosen the hose bracket near the belt tensioner. Loosening this hose bracket will allow for you to access the bolt holding the belt tensioner in place more easily. 

4. Next, use the 8mm socket and breaker bar to remove the bolt holding the old belt tensioner assembly to the engine. 

5. Clean the old mounting location of any rust or debris. 

6. Coat the belt tensioner bolt in some lock-tite and thread it through the new belt tensioner. Begin to tighten the belt tensioner to the engine. 

7. First finger tighten the bolt, then tighten the bolt to 89 in-lbs and further turn the bolt 90 degrees. 

8. Use the 3/8” breaker bar to move the new belt tensioner assembly and slide the belt back on. 

9. Use the 10mm socket to re-tighten the hose bracket to the engine. 

10. Check that the belt is properly seated on each and every pulley. If the belt is not properly seated it may cause damage to the belt and/or components of the engine. 

Installation Instructions written by AmericanMuscle customer Roberto Fernandez 8/21/2015