When reinstalling the cold start injector on our '81 245DL, I found the threads in one of the two holes on the manifold are shot. Not sure if I did this by overtightening or cross-threading the cap screw upon install, or if it happened during removal.

Have any of you dealt with this situation before, and if so, what was your solution? I was thinking of just re-tapping the holes, possibly for a slightly larger screw. The injector is currently flush with the manifold, but seems a little loose. I don't want to create a vacuum leak.

And while we're on the subject, does the mounting flange of the cold start injector require some gasket material, or is the o-ring sufficicent to prevent a leak? When re-installing the injector, the o-ring didn't offer up as much resistance as, say, a fuel injector o-ring when re-installing.

Any and all advice would be appreciated. If I decide to re-tap, this will actually be my first time using a thread tap. I certainly don't want to make the situation worse...

Thanks,
Greg