Yun, which bolt? The top bolt that holds the bracket to the housing? Check that one as it may take a thread repair kit....I botched the initial threads on one of the other bolts that hold the housing halves together, and they are not blind holes so I just ran a tap thru and bought longer bolts. I think it was the bolt without the bracket....it was a few yrs ago so I don't remember exactly. I was thinking I was screwed, but when I looked & found that the holes were not blind I was relieved.
I'm almost positive the bracket to housing bolt is blind....you would think I'd remember, damn senility stinks!
Tom