They’re M26-1.50 36mm. I have checked every local part store and not a single one of them has this size in stock.

I desperately need to change my lower ball joints tomorrow, can I re-use the nuts that are on there if I’m careful during uninstall?

The only thing that worries me is having to re punch them into place, is there any safety risk in doing it twice on the same nut?

 

You can reuse. Just make sure it is punched after install, so the nut will not back out (I'd give the same advise with a new one).