I've got some stripped threads at the end of the rotor shaft on a GM alternator. No one that I've talked to seems to know the correct die size to use to clean up the threads. 5/8" is too small and 3/4" is too large. This leaves 11/16" which must be custom to GM, as I can't find this die anywhere. I thought it might be 3/8" pipe, but no luck with that either. Any thoughts on where I might find the correct die? Thanks for any help
I'm not sure what the size is but if 5/8" is too small and 3/4 is too big then it is likely 11/16. Its definitely a fine machine thread which would make it an 11/16" - 16. It would be good to verify the thread size because they aren't cheap. Look here. http://www.mcmaster.com/#dies/=70mwm3 Any competant tool supply store can get this although it may have to be ordered. If you have a local machine shop try stopping in with the rotor and if you ask nicely, or bring them donuts they may run a die on it for you no charge.
Hi Jason, Thanks for the info and link. I guess I'll have to try the donut thing though. If you check through the McMaster-Carr die sets, 11/16" is not a standard size which is why I indicated that it must be a custom GM size. 3/8" pipe is awful close, and might be the answer since I do have a tap and die of that size. I think I'll stop at a few machine shops first though. Thanks again, Doug
It may be way easier to find a new alternator unless you are trying to save matching numbers. Still you can find those to. Don't kill yourself over it.
If you want to keep that alternator for the #,just change the rotor,and that way you won't have to worry about the treads.Any alternator will fit,just make sure it's working.BrunoD.
