Was looking at the rear axel castle nuts and while they are OK thought it might be wise to replace.

Part number 901 332 806 00 in PET does not show the size or thread pitch. At $15+ from some places I thought I would see if it were available from McMaster Carr.

Can measure the size and height but no clue on the thread.

I'm sure someone has those used, same part 914/4 - 914/6 - early 911, just do a WTB in the parts section. Or check out the samba.

Don't replace them unless you have to, they are a huge pain in the butt. Use the real parts, a substitute is not worth taking a chance on.

--DD

They are fine to reuse unless damaged.

Just measured my spare axle and it's 20 mm thread OD and my US thread gage hows approx 16 thds/inch, which converts to 1.5 mm pitch,
so it's M20-1.5,. a fine thread by metric chart

https://www.belmetric.com/steel-castle-nuts...inc-p-3060.html
Probably still $12 after shipping.
But like Mark said we use them over and over.
Only thing to add. Try and clean the exposed thread before you back them out.
We lost a couple stub axles on the rally cars from the salt air and sand in Baja.