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How to Install Steeda Underdrive Pulleys for your Late 2001-2004 Mustang GT

Installation Time

2 hours

Tools Required
  • Ratchet
  • Impact wrench
  • 15/16” Socket
  • 11/16 “Socket
  • 10 mm Socket
  • Three-bolt puller
  • Floor jack
  • (2) Jack stands
  • Torque wrench
American Muscle
Shop Parts in this Guide

1) Raise the front of the vehicle and place on jack stands. Set the parking brake and place the transmission in gear/park. Never work under a vehicle that is only supported by a jack.  

2) Using a 10 mm wrench, remove the three bolts on the radiator reservoir. Move the reservoir to the side to create more room to access the pulleys. 


3) Loosen the alternator pulley with an impact wrench and 15/16” socket. Don’t remove the pulley or belt yet. 

Note: The underdrive alternator pulley is not used on the Mach 1. Skip this step. 

4) Using a ratchet and 10 mm socket, loosen the 4 water pump pulley bolts.  

5) Remove the belt, water pump and alternator pulleys   (Loosening the belt tensioner will make belt removal easier).


6) Using an 11/16” socket, remove the harmonic balancer bolt. An impact wrench will be required for cars with an automatic transmission.  

7) With a three-bolt puller, remove the crankshaft balancer/pulley. 


8) Apply a bit of high temperature silicone sealer to the keyway slot on the balancer pulley. Line up the keyway and install the pulley.  

9) Use the longer bolt supplied with the new pulleys to pull the balancer onto the crankshaft. Don’t tighten the bolt all the way. Damage could occur if the bolt is over tightened. Once the pulley is on far enough for the factory bolt to reach, remove the longer bolt and install the factory bolt. Torque the factory crankshaft bolt to factory specifications as follows:

1) Torque to 66 ft-lbs 

2) Loosen bolt 1 full turn 

3) Torque to 37 ft-lbs 

4) Tighten bolt an additional 90 degrees   


10) Install the water pump and alternator pulleys.  

11) Install the belt following the factory routing, then tighten the water pump and alternator bolts.  

12) Start the car to make sure the belt is running properly. Turn the car off and inspect the belt to make sure it is aligned properly. 


This guide applies to Vehicle years: 2001, 2002, 2003, 2004 and Submodels: GT