Stripped Alternator threads?

[Phil Noble]

I was driving my 911sc yesterday, and the alternator belt broke. I had a spare, but the last 1/4" of threads got stripped on the alternator(and completely stripped nut) while taking the nut off. I was able to use a few threads(maybe 2), and a different nut to get home. What do I need to do now? Can I re-thread the alternator? Or do I have to get a new one? Any help would be great.

Thanks,
Phil Noble
1979 911sc

[Formerly Steve Wilkinson]

The PO of my car--'83 SC--had cross-threaded the alternator nut, and when I took it in for a rebuild at the local shop, they simply rethreaded it an American size and put a domestic not on it. In the process, the shaft got slightly shortened during the cleanup and the rethreading was slightly cockeyed, but it seems to work anyway. I'd just have it rethreaded and give it a shot. What's to lose except a few concours points?

Stephan

[Rufblackbird]

I recently had this problem, and found out that nobody, I mean NOBODY had the right die to rethread my alternator shaft threads. My alternator's probably original, with the 1.00 pitch threads. I called my local Snap-On truck guy, and found out even they don't have a M16X1.00 die. However, he suggested to me to use something called a thread file. If your threads aren't damaged THAT much, it still can be saved. If not, you just might have to do what Stephan did. Anyway, the thread file basically has different pitches on each side, and you just file the threads On the four sides of the square, there is a file for each different pitch. You get the bolt or stud, and you run the file perpendicular to it, going the same way as the threads. with it. Mine worked, after about 15 minutes of filing. Here's a pic to explain how it looks like.

[Phil Noble]

Thanks for the help. The threads are completely gone on the end(the last 3/8" anyway). Without 2 spacers, I had the 2-3 threads to get a nut to grab, so I could get home. I will try to re-thread the stripped part, or re-thread it to a smaller size if the other does not work first. Any other thoughts?

Phil
79 911sc