Easiest way to press out exhaust stud?

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Jun 3, 2015
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In a bit of a predicament, would appreciate anyone's experience with this issue. The Y pipe on a 2008 G35x has rotted to the point where it needs to be replaced. My problem is with two exhaust studs pressed into a cat flange (there are two cats), there are supposed to be nuts on the Y pipe flange side that screw onto the two exhaust studs from the cat side. The nuts have completely rusted away, one of the studs appears to have threads but rust has formed over it and they can't be used without being tapped and I doubt that would work anyway. The remaining stud has dissolved past the threads and looks beyond salvageable.

The car is a beater and I'm trying to get this Y pipe replaced with the most minimum cost, don't care how ugly the fix looks as long as its functional. The plan I would like to go with is to somehow remove the studs and replace them with bolts. I think drilling is going to be difficult so out of the question. Hammering the studs is out of the question as well since I worry I might break the thin flange or destroy the cat. That leaves me with one last option, press it out using a C clamp and some sockets to act like arbor plates on a press.

Has anyone tried using a C clamp to press out splined exhaust studs? Is this a stupid idea? When I google it, most people say hammer it or even cut from the side or drill so I'm wondering if there's a reason people just don't do it that way. Also will heat make pressing out splined in studs easier? If so should I heat up the stud or the flange ear to ease it out?

Here's a picture of the area and the two studs:

image000000 - Copy (2).jpg


If I can't press the studs out (though I would like to), one last alternative plan I have is to bypass the flanges entirely, by using split flanges (Nickson makes them) to make two "new" flanges rotated slightly so that their connecting bolts will clear the ears and existing studs. On the cat side this is a little concerning because the cat widens and it might conflict with the diameter of the split flange, unless I use a dremel or something to saw the round parts of the studs off to make the split flange as as close to the existing flange as possible. Something like this:
1664080490872.png
 
Joined
Jun 19, 2020
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Iowa
Grind the stud flush on both sides and smack it with a punch. If that doesn’t work I’d drill them out. Your c clamp idea is interesting. Let us know if it works.

Just my $0.02
 
Joined
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Depending on your skills you may or may not be able to do this at home, otherwise an exhaust shop can do it easy. Cut out the flange. Install new y-pipe. Either weld on a new flange on the cat or just eliminate them both with a piece of straight pipe.

I once had a header flange get crushed and the exhaust shop had a straight pipe in there, in about 10 minutes and a case of beer. That was some time ago, it might cost 2 cases of beer these days.
 
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Depending on your skills you may or may not be able to do this at home, otherwise an exhaust shop can do it easy. Cut out the flange. Install new y-pipe. Either weld on a new flange on the cat or just eliminate them both with a piece of straight pipe.

I once had a header flange get crushed and the exhaust shop had a straight pipe in there, in about 10 minutes and a case of beer. That was some time ago, it might cost 2 cases of beer these days.
This ^^^^^^^^^^

Some things are just not worth the time, effort, and aggravation to try and do yourself. This is one of them. I see you live where road salt is as common as crime without punishment.

Exhaust shops in your area see this every day. They have all the necessary tools, welders, and torches, and know every trick in the book. Whatever they charge you will be worth it. And it will be professionally repaired so you can forget about it...... Until another Winter gets to it.
 
Joined
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9200' Colorado
This ^^^^^^^^^^

Some things are just not worth the time, effort, and aggravation to try and do yourself. This is one of them. I see you live where road salt is as common as crime without punishment.

Exhaust shops in your area see this every day. They have all the necessary tools, welders, and torches, and know every trick in the book. Whatever they charge you will be worth it. And it will be professionally repaired so you can forget about it...... Until another Winter gets to it.
And nothing in the world will make that original stud come out without destroying something else. It is wayyyyy too far gone.
 

SammyChevelleTypeS3

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This ^^^^^^^^^^

Some things are just not worth the time, effort, and aggravation to try and do yourself. This is one of them. I see you live where road salt is as common as crime without punishment.

Exhaust shops in your area see this every day. They have all the necessary tools, welders, and torches, and know every trick in the book. Whatever they charge you will be worth it. And it will be professionally repaired so you can forget about it...... Until another Winter gets to it.
I gotta agree.
 

JTK

Joined
Aug 14, 2003
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14,909
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Buffalo, NY
Like said, if you can get a grinder in there, that would probably be the most feasible DIY method.

I know we throw the exhaust shop recommendation out there all the time. I do it too, but do these even exist in the rust belt anymore (assuming that's where you live)?

Pretty sure all that's left is national chain type places that do general automotive repair, including exhaust work, but in the rust belt, they'll want to replace instead of repair.

Your best bet is find a privately owned repair shop and see if they'll give it a go without insisting on replacing entire sections.
 

Omahaug

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Jun 3, 2015
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New York
Thanks for the replies guys, I'll try to fit the split flange and if it works it works, otherwise I'm going to call it quits. FWIW originally I told them to take it to an exhaust shop or an indy garage, to have them blow the studs out with a cutting torch or weld a new flange on. They don't want to go to a shop though because of cost, or they don't want to get ripped off. I'm always generous with my time because I don't want people to feel bad, but lately I've started to change my viewpoint and realize sometimes it's better to just say NO, leave them to figure their own problems out rather than making them mine.

Thanks again!
 
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