I'm working on the exhaust and I'm stuck. It is the original exhaust; the exhaust pipe had a major rip in it near the muffler where a heat shield was welded. Sawzalled the exhaust off and took my trusty Dremel to cut off the rusty bolts holding the exhaust flange to the cat pipe. But they're not bolts, the pipe has studs at one end, nuts at the other. Okay, I cut those nuts off expecting everything to come apart. Not happening. Apply heat (Mapp torch - good thing I fixed those gas lines, eh?), bang the stud ends with a BFH and a drift, no movement at all. From all appearances it's like the studs have somehow affixed themselves into the cat pipe flange.

Can anyone tell me how to get these two pipes apart short of going to a muffler shop?

 

Chemicals & BFH. It is "only" rust.

You could drop the entire system, only 3 more nuts to go.

 

Bigger BFH! Or drill out the studs, I used an air hammer to drive out the OEMstuds.

 

It's crossed my mind.

Thanks, guys!
Another question: The flange on the cat side is supposed to be flat, not dimpled where the bolts are, correct? The reason I ask is there are nut-sized domed bulges beneath where the nuts were, I wasn't sure if it's a part of the flange or if it's something I need to Dremel down further.

 

Before you go any further make sure the flex pipe is intact.

I don't recall any dimples, but the gaskets have some.

 

Here’s pictures of mine




The flange in the end of the catalytic converter down pipe, gasket still stuck on.



The exhaust manifold end, has an o ring groove and braided gasket

 

If you are going to start replacing the exhaust you might want to look at this web sight. They have what you will need and it bolts right up at a good price. As you can see they have gotten rid of the GM restriction at the flex pipe on the down tube.
Mandrel Exhaust Systems

 

I replaced mine with this , 2 inch stainless steel mandrel bent piece

https://rover.ebay.com/rover/0/0/0?m...2F192419804833

It helped my 2.2 catch its breath and run a touch better




Mandrel bent 2 inch tube no kinks



This bend is were you see a kink in the OEM pipe



A Venturi flange to direct exhaust gases



A 3/8 thick flange with a full 2 inch hole not the 1 3/4 inch OEM hole in the flimsy 1/8 factory flange

 

Than you all, MUCH appreciated!