Polo Vert

I have one last bolt to get out so I can drop the exhaust and swap my rearend. On the driver's side exhaust flange where it meets the converter there are the two studs and then one bolt. Had no problem getting the nuts off the studs but the bolt just doesn't wanna come out. I've soaked it several times with PB Blaster and Aerokroil and then broke out the propane torch and put the heat to it. Nothing has worked so far. Any ideas on how I might get this bolt out without breaking it? Thanks!

WVZR-1

Since you've tried all of the conventional chemicals except the mix 50/50 of ATF/Acetone you might BUT I believe since it's a horizontal fastener most chemical solutions run off before penetration. What doesn't often get mentioned but would be maybe the next best approach is the "WAX with heat". That just might be the ticket for you.

I've seen it used, I've used it maybe 3 times just because a friend was there and said "watch this" and there always was wax in the shop. It could very well be worth the effort.

Wax was used by many shops a long time ago before some of the penetrants were available. Now that the "FEDS" control everything who knows how effective any of them are. Name recognition might account for the sales and maybe not "performance". I was using Kroil just yesterday. I'd like to think it's the stuff I've always thought it to be.

Polo Vert

Now that u mention it I remember an old machinist guy I know get a broken bolt out of a cylinder head by melting a birthday candle on it. Its worth a shot...Thanks!

mtwoolford

Bee's wax works wonders, it will melt and penetrate at higher temps than various penetrating oils which will just flash and evaporate until things cool down a bit. Also try heating that sucker as hot as you can, and the press an ice cube directly into it; heat, cold shock, penetrating wax and fluids will break it loose.

Tom400CFI

Yes. More heat. Heat will work. You need more heat. If your torch had enough BTU's to get the flange that the bolt threads in to, glowing cherry red, that would be ideal. Your torch doesn't have enough BTU's however, so you simply need to spend more time on the flange w/your torch. Probably a good 4-5 minutes. Heat will get it out.

Polo Vert

I'll go get one of those yellow MAP-pro torches. My propane one is about empty anyway.

WW7

I've used an impact gun on some hard to remove bolts, the impacting motion will sometimes work when a standard socket won't do it... with using heat, this will usually work when nothing else will....WW

auggy

Try 50% acetone with 50% auto trans fluid and give it time. kroil the best otc you can buy with liquid wrench being second. This mix is better but no spray unless you go out and buy a hand sprayer

DinoBob

Heat and candle wax. Got exhaust bolts and studs off of a '60 Buick for me that were prehistoric in appearance. OxyAce was needed for that cherry red glow.

Joe C

all of the above posts have good information - . this may, or may not help, but i'll just to throw this out -- I've replaced exhaust systems on four different C4's, every one of them, solo, by myself. all four, I dropped as a one piece assembly. the three L98 cars, unbolted from the exhaust manifold, a couple center hangers, and the rear muffler hanger bolts. in fact, my 85's exhaust is sitting in my driveway as we speak. my 96 was a little different. the cats have two different connections - one slip fit, and one flange. a bit tricky, but it still will come out in one piece. to the OP, good luck on your repair....

grumpyvette

http://garage.grumpysperformance.com...07/#post-43180

1984Z51auto

This one came back from the dead, 2015!?

ex-x-fire

In the rust belt, this style of GM fuel filter has a tendency to rust up. The line nut freezes to the line, I've used that freeze off stuff and it works. Just give it a long blast like in the directions.

Hot Rod Roy

Welcome back Paul! Long time, no see! Hope you're doin' good!