One of the studs on my driver side catalytic converter flange, where it connects to the y-pipe section of the exhaust, is stripped and needs to be replaced. Local shop already ran a die over it to clean it up but the threads are too far gone. I am trying to figure out if this is something I can tackle myself so I need to have the following questions answered:

1) Are these studs threaded into the flange, pressed into the flange, or tack welded into the flange? (or some combination of the three)

2) Assuming they are just pressed into the flange, would it be feasible to heat the surrounding flange area with a small propane torch (i.e. $20 Bernzomatic from Home Depot) and then tap the stud out with a hammer? Or is there more involved in this?

3) Once the stud is removed, is it plausible to use a bolt and nut instead of replacing the stud? Without getting back under the car I cannot remember whether there is enough clearance on the backside of the cat flange to slide a bolt in.

Thanks in advance for any advice.

 

as far as i know, its threaded in. a stud extractor should take it out no problem..

 

It depends on the cats, I've seen threaded in and I've seen pressed in. Don't over-think this…just cut it off with a angle-grinder or dremmel and drill it out…put a grade 10.9 nut & bolt combo in. You can usually find 10.9 rated hardware at most autoparts stores…something like a M8 or M10 bolt would be find. Put anti-seize on any bolts that are either off or you can remove and reinstall.

 

Thanks for the advice fellas. Tackled it today and the stud was pressed into the flange and had a knurled shank just like a wheel stud. I ended up cutting into the head with a reinforced cutoff wheel on my Dremel but unfortunately the wheel was not large enough in diameter to cut all the was through before the chuck hit the flange. I ended up cutting the threaded portion off flush with the flange and drilling out the rest. It was a stubborn sucker. Replaced it with an M10x35 screw and flanged nut.

 

Glad it worked out - do you have any pictures?

 

Damn, sorry. Did not think to take any photos in process.