I replaced the wiper transmission on my car over the weekend and damaged the ends of the threads on the stud the holds the wiper arm. I should be able to repair the damaged threads with a die. Store manager at NAPA said to use the same diameter as the original - 10mm. I've never done this but it seems logical to step down to at least a 9mm. If ya' don't know, ask so I'm asking what ya'll do? Advice greatly appreciated.