The bolt that holds up the exhaust on the rear of the car is stripped. Not the nut part of the bolt itself, but the threads on the underside of the car. The bolt spins endlessly. Any ideas as to loosen it and if I do, will I not be able to get a bolt back in tight? Sorry for not having pics.

 

How about grinding the head off of the bolt with an angle grinder. Then you can at least get the exhaust system off. Or try gripping the bolt with big vise grips. Pry the vise grips with a screwdriver as you turn the vise grips--maybe the threads will catch and the bolt will turn out.

 

That bolt is a serious bitch. Try putting a prybar up there and applying pressure between the rear tub and the bolt head while unscrewing it.

If you cut the head, the exhaust will come down, but how will you get it back up?

Once you get the bolt out, get yourself a Time-Sert and a new bolt.

 

If you ground the head off the bolt, could you just pound/chisel it out and replace it? That might be a terrible idea depending on the position of the bolt but i'm not quite sure which bolt you guys are talkin about lol.