I tried to install an exhaust system this weekend that I picked up off craigslist. I spent 2 days trying to bust loose the factory nuts but they were rusted too bad. Two of them I stripped and the others would never budge. You couldn't tell where the started or stopped. I decided to just cut the exhaust out in 3 pieces and I cut the nuts off at the flange that meets the cats.
Does anyone have a suggestions on how to get the bolts out now? Would I be better off drilling the four bolts or just cutting the round head off from the cat side?

 

Heating them with a torch is one of the best ways to free up rusted bolts.

 

I used PB over night. I used PB again this morning and then tried to torch right away and cooled with PB. I could never see the end of nut. I even tried an impact gun and that didn't budge them either.

 

The truth. Get an acetylene torch and heat em up until they are glowing. Then take a ratchet and take it nice and easy and they should come right out.

 

I already cut them so I can't try the acetylene torch method. I have the studs still in the flange to the cats. Whats my best way to get them out? Are they welded in?

 

Before you burn down that IP coupe run it by your local muffler shop and have them finish the job for you. They deal with your rusty bolt issue 6 days a week! Without a rack and the correct tools you could be creating more damage than the new exhaust is worth....Gary

 

I would have to have it towed. The stock exhaust is already cut out. I just need 4 bolts removed that I cut.

 

heat up the flange around the bolts. heating the bolt up will cause the bolt to swell making it harder to get out. you want to heat up the flange around the bolt and make the flange itself swell. hence the term "thermal expansion". but heat it up and spray it with PB blaster or some sort of penetrating oil that doesnt evaporate completely. after a while grab the bolt head with a vice grips (really tight) and torque on it until you can get the bolt to start to spin in the flange. then put a punch on the end of the bolt where you cut the nut off and grab you "precision poundometer" and hammer away at it until the bolt comes out.

its time consuming but it works. I just did this last weekend on my rx7. plus then you dont have to pay to have it towed and dont have to pay to have some bolts removed. its not complicated, just takes some neanderthal-esque effort on your part.

 

shoot it with an AR

 

^ I can get on board with that

 

I give up! Screw it. I mise well buy hi-flow cats now and then I don't have to deal with these bolts! I'm coming up on 100k miles so I'm sure they are at the end of their life.

 

I was in the same boat on my Y pipe. Holy **** they should not use the same material for hardware and exhuast.. thats just asking for rust.

PB'd, deep creep'd, benzene torched.. nothing. Had to borrow an oxy-acetylene torch and impact it off while it was glowing. Sucks that you broke the bolts, good luck OP.

 

That is where I am having trouble. I am going to attempt to take that cats off. If I can't break the top bolt loose I will just have it towed to a shop and have them deal with it. Now I just need to find a deal on cats and decide which ones I want.

 

I had the same thing happen on my car when I was attempting to put a new exhaust on. Surprisingly, I was able to remove the 3 bolts/nuts from the exhaust manifold to the cats but couldn't get the 2 bolts on each side of the Y-pipe loose. I tried PB, a torch and finally ended up breaking my breaker bar. I was going to cut it out but decided to give it a break until I get the car reinspected. Good luck!

 

I gave up and ordered hi-flow cats. They are supposed to be delivered Wednesday and I already talked to a shop about installing them. He told me he should be about an hour to get them swapped in about an hour and charges $60 an hour. For that price or even $100 if it takes him a little longer, its worth it.