I have managed to shaft one of the threaded holes in the rear sub-frame

(the one that holds the lower suspension arm to the sub-frame) and wondered if anyone might know what thread tap I need, and if there is anything else I could do? I have only mashed the first thread or so so the bolt won't bite.

Having looked atthe bolt, it seems to be an M14 x 1.5 thread.

Can I just run a tap through the first couple of threads? I don't want to have to replace the sub-frame.
