exhaust stuck to cats

[Formula 170]

My oil pan gasket is leaking so while I'm there I decided to change the muffler as well. My 91 has the OEM muffler and after 21 years and 130k miles all the nuts are badly rusted. I was able to remove all six nuts, 2 bolts on one of the cats broke. So, it should be easy just to pull the muffler off, right? Wrong. The muffler is still solidly attached to both cats. I tried banging on the muffler as I won't use it again, no luck.

Any ideas on how to remove the muffler? Also, I want to use the cat with the broken bolts, can I just get two new bolts welded on?

Thanks!

 

[swimmingpie]

Try spraying some penetrant on the stuck part. Something like PB Blaster might help. If not, maybe heat would do it.

 

[Formula 170]

Tried PB blaster. The nuts are off and the two pipes are still stuck together.

 

[ThumperAC]

I had to soak in PB blaster overnight to get my cats loose from the headers.

 

[Formula 170]

Here are some pics of what I'm talking about. All nuts removed (or broken) yet still stuck tight.

 

[Moses]

Ummmm..

Did you use a breaker bar?

Looks like you broke the bolt heads off living the bolts still screwed in....

Going to have to drill them out or get a tap and knock them out.

 

[angus]

Seriously you just need a real BFH - take the heat shields off and hit it right at the joint between eh two flanges, it'll come off.

Once the card are off you can put them in a vice and knock the studs out and then replace them, not rocket science but not easy either.