Borrowed from Ultimate Subaru Message Board 3.8.00 posted by Eric Zap-Chairiotsu

If the hole the post is in gets stripped, it isn't a big deal to fix it. At your local auto parts store, you should be able to find what's called a 'Helicoil thread repair kit'. The kit should contain; 1 drill bit, 1 Tap (re-threads), several helicoils, and a helicoil installer.

The kit is kind of self-explanatory, but basically you drill the existing hole to clean it out, rethread the hole with the tap, and screw in a helicoil. The hole will be stronger than when it came out of the factory. The size that should fit (EA-81 models) is M-10 by 1.25. M-10 meaning 10 mm.

The whole process should take less than a half hour, including taking off the Y-pipe. The Sub mechanic who first told me about it said to be smart and use a post again rather than a bolt. (In case you need to take that damn pipe off again)

Should quiet that noise right down.


I recently performed this operation on my 86 HB.  I found it to fairly easy but will say this.  Drilling into your heads can play games on you mentally.  Don't give yourself an ulcer worrying about it and have some faith in your tools and handywork.  My HB is QUITE a bit quieter than it ever was before. 
ANother thing to remember is that it will need at least 2 inserts per hole, and I encountered a couple of inserts that just didnt want to cooperate with the insertion too. 

The kit was around $60 from Napa.  I found this was the only place in town that had the correct bolt and thread kit. 

Basically take your time, dont make it a 30 minute job the first time, and tell us about your success when you are through.