I was removing my exhaust from the cat back to put on a new one and the two spring loaded bolts were very rusty and one of them snapped off. Just the little round nub is sticking out now and remainder of the bolt is still stuck in the flange on the midpipe. Any ideas on how to get that thing out? The nuts on the other are side are welded to the flange and don't move. At first I thought I could cut it off and get new bolts but nothing is ever easy it seems.

 

penetrating oil and a vice grip? maybe heat up the nut with a heat-gun or torch to try to get it to expand a little

 

I had already soaked it good with the pb blaster. Before it broke I was trying to get it off with my air impact gun and it wouldn't budge. So then I ran the car to get the exhaust real hot and went at it with the impact again, and it broke. So I feel like if my impact couldn't get that thing out with a nut attached, there is no way I am going to turn it with vice grips or channel locks. I guess I'll start the car again to get it hot and give a shot though.

 

These things can get really tight if u go to autozone they sell the same screwed that fit the exhaust and cat!! Ur best bet MIGHT be to cut the screw and replace them with the new ones!

 

I have no problem with getting a new bolt. It's getting the old ones out of the flange that's the problem.

 

can you drill out the remainder of the bolt?

 

I don't think I can without damaging the threads in the nuts that are welded to the flange. I am about to throw in the towel and bring it to a shop. My 92 volvo 240 is a dream to work on compared to this rust bucket rx-8.

 

use the other nut as a guide, select a drill bit that will not come in contact with the treads. Once you hollow out the old bolt it will fall apart.

 

the nuts aren't welded on that great so you can just pop them off and use regular nuts. The new bolt kit will most likely come with them anyway. I had to when I reinstalled my cat. The stock bolts stripped as soon as they got tight so I had to use the bolts from my mid pipe.

 

That is a 5/16 drill bit in the photo and it doesn't touch the threads. The spring bolt is an M10, so anything a little smaller will be ok.

 

Thanks for the great responses. I think I would have a hard time keeping a drill straight enough. I was just thinking the same thing that LMMJ suggested, that maybe I could break the welds on the attached nut on the back and just use a new one. Then I could dremel off that lip on the bolt and be done with it. Can't believe two bolts turned into an all day job. I'm done for today - I need a beer.

 

I double wrenched a 14mm and 15mm wrench and the nut spun right off. Just watch the knuckles!

 

I drilled the bolt through, a little off-center, sadly, so there is still 1/3 of the bolt left in it, and then dremeled the lip on the bolt off. I still can't get the welded nut off the back. It's the side with the bracket for the hanger, which doesn't help. I decided to take down the exhaust at the cat so I can work on it in the open. So now I am having fun trying to get the 3 nuts off the cat bolts. They are tight the whole length of the thread. Got one off so far. Now I remember why I usually avoid DIY exhaust.

I am only trying to replace the catback with another stocker too. Original broke right off at the muffler and the inlet to the muffler was rusted through too. I have had so many corrosion problems with this car. Headlight sensors, oil cooler lines (left me stranded) and now exhaust. Oh, and my license plate is held on with zip ties in the back...those bolts and nuts rusted out too.

 

Do auto parts store have replacement springs for those bolts?

 

well it's a little late, but the best way to deal with a broken bolt(if possiable) is to take a nut. hold it in place and weld the middle of the nut to the remaning bolt. Then wrench it off. The heat from welding will break it loose and the bolt is then easy to grab with a wrench.