irobertson

Well, I got the engine on the stand today and set to work removing the exhaust.
I had to grind off all the bolts connecting the cat, and pry it off with a couple of big screwdrivers.
I managed to get one heat exchanger completely unbolted, and I got the other one undone except for two stripped hex nuts. Arrrggg!
Question is, how do you get the damn thing to come loose once it's unbolted?
They seem seriously seized on there.
I suppose that is to be expected after 23 years.

Any tips would be appreciated.

ivangene

weird, I didnt snap a single bolt swapping out my cat for a bypass pipe last month....

nothing stripped, nothing broke...in fact I re-used the hardware for a week till the new stuff arrived for replacements....

irobertson

My bolts no longer had a discernable head, just a round glob of rust. Absolutely nothing to even grab onto. It took me all afternoon to get the cat off, and I still have the remains of two bolts lodged in one of the collectors.
I knew by looking at it that it was going to be a challenge, but figured once I got the cat off and the nuts off the studs, that the heat exchangers would come off OK.

ivangene

must be salted roads in the winter?

rusnak

Steel cat bolts commonly rust/gall beyond recognition. The original bolts probably won't even fit a wrench anymore. I broke all of mine in two with my flex head socket wrench and a box end to get them off.

Some guys use ss bolts with brass nuts. I use a good amount of copper grease on the threads. You might be able to get the HEs off with tapping a plastic hammer, or heat, or a prybar, or all of the above.

MUSSBERGER

Plenty of PB blaster the night before

irobertson

Couple of pics of the rusty bits.

ivangene

DOH... she's been at the bottom of the sea matie!

rusnak

Just cut those off with a grinder.

irobertson

Yes, that's how I got the cat off, and I ground the nuts off and pounded the bypass pipe off after I took the pics. The spaces between the bolts and the holes in the flanges are blocked full of oxidized metal. I had to heat them all and pound like hell to get the cat and the x-over pipe off. I managed to do it by hammering at the ground off side of the bolts with a punch, and driving a big screwdriver in between the flanges.

Problem is, now I think I have a similar problem with getting the HEs off the heads.
I don't want to damage the heads, but I can't see getting these apart without some serious heat. That's my main worry, doing something dumb and causing more problems than I already have.

Man it will be good to have all this cleaned up and put back with proper fasteners.

irobertson

LOL, it sure looks like it.

Car came from Michigan, so I assume they use salt on the roads there, just like they do here. :-(

rusnak

Try a 1/4" steel rod, heat till it's bright orange. Then bend it at the orange spot. This will give you a feel for how soft the metal gets at a given color. At that color, tap the socket on, then quick but gentle twist should get the nut off.

MUSSBERGER

Yikes! Mini grinder and a cut off wheel.

rusnak

Yup, same as galled brake lines or a rounded off pressure plate bolt. A right angle grinder or a pneumatic cutoff grinder would do it.

Amber Gramps

I used a 1-1/2" dia. cut off wheel on my dremel.