Ok so removing the stock cat...
 

I recently got ART testpipe and I was really excited to see the difference until the shop encountered a problem.

There are 3 bolts on each sides that connects the test pipe from the header. They were able to remove 4 bolts out of 6 but they couldn't remove the last 2. They used chemicals, heavy duty gun, etc.

Any tips on removing them?

The shop said it's 'naturally' welded due to heat+cold weather:shakes head:

The only alternative I have is to get the header out, and somehow cut the welded part...

Any thoughts or tips are much appreciated !

Those bolts are called Demon bolts by many people on the forum. A quick search for "demon bolt" might point you in the right direction.

As for myself, I used a long breaker bar and got one off clean, the other snapped off. Keep soaking the bolts and make sure you're on the nut all the way with a 6 point socket, you'll get it eventually.

Mine took forever, they were a complete PITA

you can heat the PITA bolts and that will make it so the bolt contracts and you will be able to unscrew it. Most body shops will have a torch or something, that is how mine was able to install them.

I just had my HFC's replaced and if I remember correctly they broke 2 bolts trying to get them out.

:iagree:

Demon Bolts Strike Again! :ugh2:




Moved to right section

Bolts are accessed from under the hood btw using lots of extensions. I don't understand why any reputable shop isn't prepared to deal with a stuck bolt, they shouldn't just be giving up.

You should also wait until the car cools down. Metals tend to expand when hot. It may be easier to take off after it cools.

this^^^

I did it on my own so this shop needs to get back in there. breaker bar, from what I remember, 12"/6"/3-6" extention and a pipe for leverage. I cant remember if i used a swivelle socket or not......

Yes a swivel will be needed unless you want to completely remove the intakes in which case you might not need one.

^ got it I will print some of the posts and bring it back to the shop. Hopefully they will get some sorts of idea.

The shop didn't risk breaking the bolts; yet almost all my buddy with 370z broke theirs.

This is a common problem on not only the 370, but on quite a few different cars with cat/downpipe bolts/studs.

I've personally had good luck on other cars with an acetylene torch to heat the bolts and studs up before messing with them. Another option is to soak them in PB Blaster for a bit.

I used a nice impact gun with some 1/2" ext and a 6pt impact socket to rip them off. Don't even try them with a 12pt not worth the risk of rounding them... Because that's when life will get difficult

I guess removing mine w/o breaking them must make me a boss.

Anyway, I know it was mentioned already, but a shop giving up on a stuck bolt is worrisome at best...

the 1/2" extensions are key. the 3/8" flex which makes the process difficult and dangerous. learned the hard way here.