How to Change an Alternator in a Classic Mustang

The simple design of the classic Mustangs makes changing the alternator easy.

Shortly after the Mustang was first produced, the generator was replaced with an alternator. Unlike a generator, the alternator’s field rotates and the generating windings are stationary. The alternator produces electricity in the form of alternating current to charge the Mustang’s battery and supply power to its electrical system. It is for this reason that a defective alternator results in a dead battery. Replacing the defective alternator is fairly simple.

Things You'll Need

• Wrench

Instructions

1. Remove the battery ground cable from the battery with a wrench.

2. Loosen the two alternator mounting bolts with a wrench. One mounting bolt is located at the top of the alternator, while the other bolt is located at the bottom of the alternator. Note that the bracket that the bottom bolt fits through is slotted. This slot is used to adjust the tension on the alternator’s belt, and will be important when installing the new alternator. As both bolts are loosened, the alternator will pivot towards the engine and loosen the belt.

3. Rotate the alternator to access the wires connected to the back of the alternator.

4. Note the location where each wire attaches to the back of the alternator.

5. Pull back the rubber boot at the tip of each alternator wire, where the wire attaches to the alternator, to expose each wire’s retaining nut.

6. Remove the nut which secures each wire to the back of the alternator with a wrench, then pull the wires off of the alternator.

7. Slide the metal tip of each alternator wire onto its threaded rod on the back of the replacement alternator, then tighten the wire’s retaining nut onto the threaded rod. Press the rubber boot at the tip of each wire over the wire’s retaining nut.

8. Position the new alternator behind its two mounting brackets, then hand-tighten the alternator’s two retaining bolts through the brackets and into the alternator.

9. Position the alternator belt within the grove of the alternator’s pulley, then pull the alternator away from the engine until the belt is tight.

10. Tighten the alternator’s lower retaining bolt with a wrench while maintaining pressure on the drive belt, then tighten the upper retaining bolt.

11. Install the battery ground cable to the battery with a wrench.

References

• "Chilton's Repair & Tune-up Guide: Mustang Cougar 1965-73"; Chilton Book Company; 1992
• "Haynes Repair Manuals: Ford Mustang V8, 1964-1973"; Chilton; 1999