I bought a Ford 3g alternator from pull a part last year and I'm finally getting around to rebuilding it before I swap it into my s4. I found a dual alternator pulled for $15 that fits using an 18mm washer for the necessary housing clearance. When I tighten the nut for the pulley I noticed that the shaft would no longer spin. I pulled it apart and it seems that the rotor is rubbing the bolts that hold in the bearing retaining ring. It spun freely when I pulled it off the taurus at the junkyard, but it must have been rubbing before the car hit the junkyard. I didn't really pay much attention to the front side of the rotor until reassembly. There doesn't seem to be much of a collar on the shaft. I can't find a picture of the front side of the rotor online to see if something is missing or damaged on the shaft. Should I junk the rotor or can I just use an 18mm washer to keep the rotor from rubbing?