Trouble removing exhaust sections

Hi, Im attempting to do my first exhaust repairs and Im replacing the section of pipe that has the cat in it. I removed the 2 bolts at the cat end just fine but Im a little lost on the ones that connect at the forward of the cat to the header.

Ive never seen 2 nuts on a stud before….I guess they are called jam nuts? My extension was too short to get any sort of torque on them so before I do I just wanted to make sure I wasnt doing something wrong. Do I have to remove the nuts individually? Are they torqued together and that’s impossible? Or will a deep socket be able to remove both at the same time? Im planning a 10 inch extension and breaker bar to get the job done. Am I on the right track? Any tips?

 

I don't believe I have seen that before. But you should spray a penetrating fluid on it, really helps. You could remove them at the same time, but I wouldn't since you will be fighting the combined friction of two rusted nuts. If all else fails you can always split them. I would try getting a standard wrench on the outer one.

 

Ok thanks. Ive been bathing them in penetrating fluid for a few days to prep. Not sure ill be able to get a wrench on up there, its super tight. Ill try to pop one off at a time. They are studs not bolts, I had assumed going in I could just cut a bolt head off and be done.

 

and Fire! If needed you might put a torch to them. This tool is awesome, but really a torch will do the job.
https://www.youtube.com/watch?v=3ya8fxm89jk

 

That is super cool. Probably overkill to buy to pop off 3 nuts. But super cool.

 

You might be able to remove the bolt stud they are on. The end of it looks to be an E10, or an E8 sized socket. When I did my exhaust manifold sometimes it was easier to spin the stud out of the block than it was to remove the damn nut from the stud.

Getting a torch on it helps, try using acetone and ATF fluid mixture. That mixture usually isn't good to use, but sense its on exhaust you won't have to worry about ruining some finish. Just be careful that acetone is flammable.

Also give it an impact or two with a hammer, helps loosen it up. Impact wrench would help too, you can rent them from Cresco for 30$ a day.

 

Well, long story short. I got it all removed with some fluid and a good long breaker bar. Got the new cat installed and on the final torque I snapped one or the 3 studs. After 3 shops refusing to even try to remove it I finally got someone to extract it…..$350 later…