Exhaust. (Replacing rusted studs on catalytic converter)

I'm changing the exhaust from the after the cat and back. Well long story short. The studs coming off of the cat are in bad shape and I planned on just drilling them out and running some new ones but I didn't see until after I had it out that I can't because of room restrictions. That I can't feed new studs through it. So what I plan on doing is drilling them out still and tapping the holes and threading new studs into them. I plan on using locktite (sp?) And hitting it with the welder in a few spots. From eyeballing it it looks like I could get away with some 5/16 studs. But does anyone know what size the actual studs are supposed to be. Thanks.

The cat is in great shape and I do not want to have to buy a new one.

It's a 2008 aveo sedan ls. ATX.

I replaced my cat rather than fighting with re-building the mounting.

I posted on another thread (see http://www.aveoforum.com/forum/f108/...acement-21463/)

The bottom nuts on the studs on my cat were a pain. They were just rounded and rusted nubs. I took the cat off at the header. I cut the sheet-metal heat shield so I did not have to remove the upper O2 sensor and out with a couple of bolts. As my goal replacing the rusted down-pipe; I did not care if I ruined the down-pipe. I expected to get the bottom cat bolts out on the bench. ... No such luck. Broke one off. Ended replacing the cat. The studs look like they were installed in the flange before the cat was welded together. It was like it was designed to assemble easy at the factory; the possible repair/replacement was not even a consideration. (maybe a consideration; they wanted it as difficult as possible :icon_smile: ).

chuck

If there's a will there's a way. A quick stop at lowe's about $5.00 worth of stuff and an hour and a half of time (the one stud would not come out, otherwise I it would've been less than have of that). I got it done. I might hit it with the welder tomorrow to make sure those nuts won't ever come loose. I did have to grind down the nuts to make them fit. I will cut the length down a bit more but I will wait until I install it before I do.
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aguitarmn,
Looks great. As mentioned, I only speculated that it would be more trouble than it's worth and went the new cat route.

I see you are in PA. This car spent it's 1st 12 years in Pittsburgh and its last in Virginia. I even had replace the transmission to radiator lines because they rusted out.

chuck

Everything here in pa rusts. They say snow belt but it's more like rust bucket. I got some red threadlocker I'm going to apply that later.

Nice work, aguitarmn. Thanks for sharing the pics.

Thanks. New to this board. But not new to the automotive world. I got it all back together now. I ended up welding them in place. I couldn't get them loose again to use the threadlocker since I already cut the heads off. It was a good excuse to use my new welder.

I had this issue when I replaced the front exhaust pipe only I failed to successfully drill the studs out of the cat. My solution was to weld the front pipe to the cat and plug weld the holes which thankfully can be snaked back under the car welded as a whole. So this is a possible option to pursue if anyone's unsuccessful and has a welder.

Figured it wouldn't hurt anything and if I needed it separated at some point I have an angle grinder :)

You can apply red to a fastened . After it " sets " , heat is the way you force it to release . So , I doubt it eill make much difference on that application .

Sorry to be a party popper . :-(

God bless
Wyr