At this point, if the threads are knarfed, see if you can drill tap to next size up, metric or inch. Then, regardless, switch it to full depth engagement studs which have been Loc-Tite'd in, now that it is weak and been pulled out once. Then re-attach with thick flat washers and nyloc nuts. You'll never have to look under it again.
You may be able to clock the housing 45 degrees and re-drill to give you fresh threads to work with. Or, worst case, if same material, and it sits flat, just have the adapter welded to the case. Even that move, though a little drastic, would be better than having to replace it entirely.