How to Replace the Tensioner Pulley on a '98 F150

The three engines available in the 1998 Ford F150 employ a serpentine drive belt system to power the engine accessories. Without a serpentine belt to transfer torque from the crankshaft pulley, the alternator, power steering and air conditioning would not function. An automatic belt tensioner holds the serpentine belt onto the pulleys; this is done via a spring-loaded base that uses an arm with a pulley attached at the end to apply tension to the belt. If the tensioner pulley incurs damage (such as an internal bearing failure or external damage to the pulley face), replacing the tensioner is the only option of repair.

Instructions

1

Open the F150's hood. Examine the belt routing diagram, adhered to the fan shroud, to locate the automatic belt tensioner in the serpentine drive system.

2

Rotate the automatic belt tensioner counterclockwise to relieve tension on the serpentine belt. Slide the belt off the alternator pulley with your free hand. Rotate the automatic belt tensioner back into place and remove the tool.

3

Remove the three bolts holding the automatic belt tensioner to the front of the F150's engine, using a socket wrench and 13-mm socket. Pull the tensioner out and set it aside.

4

Hold the new automatic belt tensioner in place with one hand while threading the mounting bolts in with your other hand. Do not start the bolts with the socket wrench, to avoid cross-threading them. Tighten the bolts with the socket and wrench once they're hand-started.

5

Rotate the new automatic belt tensioner counterclockwise, far enough to slip the serpentine belt over the alternator pulley. Rotate the new automatic belt tensioner back into place and remove the tool. Make sure the belt is traveling across every pulley in the system evenly before starting the engine.

6

Start the F150's engine and verify the belt is traveling properly. Close the hood.