Ok I was taking off my stock exhaust today I got the muffler off no problem one bolt broke but it just slid out no big deal I was thinking about cutting them anyway but decided to try with a wrench. Well I go to take the mid pipe off and where it connects at the cat I got the bottom 2 bolts out no problem but the top one broke off. Well I took the pipe down figuring I would just put a new bolt in there. Well I went to try to hammer the bolt out and the 3 bolts that go through the flange on the cat then through the flange on the pipe than have the nut on them to hold it together well they don't seem to come out when I hit them with a hammer. It looks like the shaft may be threaded or something not really threaded. The heads of the bolt is rectangle not like normal bolts. Right now these still go through the flange on the car. How the heck do you get these things out? Do you just knock them out with a hammer or is there another way to get them out? Thanks.

 

heat them up and pound them up, you can also help crack it loose by getting it red hot and then holding ice (dry ice is even better) up to it

This will help it rapidly contract and hopefully break the rust, all the exhaust I've ever messed with is standard bolts with a nut on the end. If you're replacing the exhaust can you just grind it off or drill through it?

 

thought I might just try drilling through it although it wouldn't be easy but we finally got it out hammering it. It appears to have a spline on it like it was pressed in there or something.

 

i cant follow your problem very well, but it looks like we're in the same boat...none of mine broke off, but the passenger side one is threaded, and the nut wont stay on.....im prety sure they must be pressed in, and im wondering if they even are removable....im gonna email kteller this week about a resonator.....

 

Yeah, they've got a splined shaft like hub studs. They're a pain.

I tried to get a gear puller over there & press them, 'cause I didn't want to hammer too much & break up the catalyst monolith. Couldn't get 2 so I drilled them. Then I used normal bolts.