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Gutting precats, replacement studs/sizes?
Posted: Wed Apr 08, 2015 3:03 pm
by montyp
Planning to gut my precats and fit a millteck cat back this weekend, would like to have replacement studs ready in case the worst/inevitable happens . . .
The only kit I can find is from ECS in the states, not much use for this weekend, could anyone point me in the direction of a UK supplier? Or tell me the diameter of the stud?
Is there any reason I shouldn't use a bit of stainless steel threaded bar and a few nuts?
Thanks for any help!!!
Re: Gutting precats, replacement studs/sizes?
Posted: Wed Apr 08, 2015 3:42 pm
by JCviggen
They're regular studs, you should be able to find them just about everywhere including VAG dealers. M8x30
p/n from Audi 0445125
Re: Gutting precats, replacement studs/sizes?
Posted: Wed Apr 08, 2015 6:03 pm
by montyp
Thanks!
Re: Gutting precats, replacement studs/sizes?
Posted: Wed Apr 08, 2015 10:24 pm
by Lukes3
Have fun getting them out!
Re: Gutting precats, replacement studs/sizes?
Posted: Thu Apr 09, 2015 7:54 pm
by montyp
Just had the car up on axle stands to clean the nuts with a wire brush and apply some penetrating oil before tackling this weekend. . . someone has had a go at the 2 that are visible on the drivers side, completely rounded!!!!
Not sure its even such a good idea trying anymore. . . . . .
Re: Gutting precats, replacement studs/sizes?
Posted: Fri Apr 10, 2015 7:51 pm
by chris_m
Mate I had an absolute nightmare with mine. The access is rediculous and it must have took 8 hours and some to get them all out on a hydraulic lift and plenty tools. 2 studs came out, the other 4 snapped out. I ended up drilling the holes larger as the studs had to be drilled out with extreme difficulty. I put nuts and bolts in place of them. I might have the studs and nuts I bought with the same intention lying around if you want them. I will be well impressed if you take me up on it though. I did begin to wish I had never started so be prepared.
Re: Gutting precats, replacement studs/sizes?
Posted: Sat Apr 11, 2015 5:37 am
by voidopolis
so, I was in the same boat - I read a bunch of guys online who had done this. I tried soaking the bolts in PBBlaster, used a wire brush and I even tried heating them with a torch myself - but I was too timid with the heat for fear of ruining something. I snapped a stud and the others wouldn't move at all. so, I took the car to a place that does custom exhausts. I had them take out all the bolts and put it all back together with anti-seize so that I could do the rest of the de-cat myself. They were able to get all of the studs out (including the one I snapped off) without problem - no drilling or retapping - including the lower bolts. It took them less than an hour and the charge was under $75. they said its no problem if you heat the bolts enough - like RED HOT.
So, my advise would be save the frustration and just have someone take the studs out or get your torch out and heat the hell out of them. FYI: getting out the sensors is a pain too.

Re: Gutting precats, replacement studs/sizes?
Posted: Sun Apr 12, 2015 11:52 am
by montyp
Thanks for the insight, voidopolis i have read your thread on another forum about this!! Your experience is one of the ones that made me decide not to go ahead.
Got the cat back fitted in about and hour or so and left the downpipies alone. I'm going to try and find a second hand pair, gut them, and get a
Shop to fit them, then sell my old ones.