Replacing gasket in exhaust

[Retrospekt]

I have a leaking gasket in my exhaust between the headers and the front pipe. It's a circular gasket about 4 inches in diameter.

What is the best way to unscrew this portion? I have some P Buster I could use, but I used that for undercarriage work and barely got the bolts off.

Should I run the engine for a little while to heat the bolts up, then spray it with P Buster?

[DxElite]

I've taken that joint apart before for an oil pan gasket replacement on a friend's Camry with about 60K miles.

I sprayed it with PB and with a 2 ft breaker bar it was still stuck so I brought out my pneumatic impact wrench. Ingersoll Rand "nut busting" 1000 lb/ft torque and was able to get the first nut off but the 2nd one broke my socket. It was Craftsman so I got a free replacement and tried at it again and the last 2 came off.

I don't like heating bolts since I'm prone to burning myself so I have never tried the heat thing.
Lately I've looked into other methods for removing stuck nuts/bolts and found an alternative to heating, rapid freezing.
Found 2 products called "Freeze-off" by CRC and "Freeze & Release" by Loctite. Haven't tried it myself but the logic behind it makes sense, might be worth a try.

[mnyball34]

Your best bet is to soak it repeatedly with PB Blaster or something like it over the span of a week or so. Then try to work the nuts back and forth with hand tools until you can get them free. An impact wrench is handy, but the studs in the header are very prone to snapping off if you use that much force.

[CJCride]

Switched all the exhaust bolts, nuts and washers to Stainless Steel plus a bit of high temperature Anti-Seize. Years later they came off like they were put on the week before.

[Mike Gerber]

Karl,

I have to agree with myball34. Soak it, soak it and then soak it some more over a period of days with PB Blaster and then try to loosen it. Do this with the engine cold so the PB Blaster has time to work itself in, before the heat in the exhaust evaporates/burns it away.

This may also be something better left to a shop that can heat those bolts with a torch before trying to remove them, if you don't want to take the chance on braking them yourself. I have a good independent muffler shop in Rolling Meadows that I use. This guy is pretty reasonable. There is no guarantee that they won't break after being heated with a torch; but it is less likely. Left me know if you want this guy's address and phone number. You can give him a call and ask what he would charge to do this job.

Mike

[Retrospekt]

Alright, time for some pro tips since I just slaved over this for about 4 hours.

Never, ever try this. Ever. It's the worst thing you'll ever have to do.

I got 2 out of 3 bolts off in about an hour, I thought those were ridiculously hard to get off. The last bolt took up the other 3 hours, and I'm pretty sure I only got about half the tread out so far. It took all the effort I have in me to turn it about 1/10th around. That's how terrible it was. I'm not that weak either.

To make it worse, it's about impossible to fit a breaker bar anywhere near here. To make it even worse, it's so rusted you don't even know what size wrench to use (14mm). I was using 15mm at first because it fit snug...and the wrench slipped on me about 10 times.

All in all, I lost 4 hours, got all dirty, and bled all over my hands to accomplish...nothing. I'll keep soaking it for a few days and try again, but man. That was awful.

Oh, and I've never been dirtier in my entire life. I don't think there is a clean inch of skin on my entire upper body.

[DxElite]

Try this Freeze-Off .
Just happened to find it after a bit of research on seized nuts over the weekend. Haven't tried it myself, but it's worth a try.

[falken]

I'm soon replacing the whole downpipe due to a hole in the flex pipe... A mechanic told me to tighten the nut first, if possible, then PB blast the threads, work the nut back/forth while pb blasting the studs to death. If this doesn't work... I'll go buy a grinder and be done with it. The oem studs/nuts aren't expensive through toyota.. Goodluck with the repairs

[Jimnist]

I feel sorry for you guys. My 1990 gen 2 came off pretty easy with a breaker bar and about 2(or 3) of those long extensions (about the length of the case it came in) and attacked it from under the car. That cleared it of everything and i got some good leverage on it.

[CJCride]

Hear Ya. Tighten the nut a bit, wire brush the threads, more penetrating oil.

Coal Miners are probably dirtier.

[Retrospekt]

I would do that, but here is the weird part.

The first nut came off like it's supposed to, with the actual bolt staying in the header. The second didn't do that. I'm guessing the nut is so rusted on there that I just kept unscrewing, and I unscrewed the whole bolt out of the header. The third is doing the same thing, and there isn't much I can do about it because there is no way of fastening the bolt and only unscrewing the nut...it's too rusted.

I'll go borrow a breaker bar, though I'm not sure how to fit it in there. Suggestions?

[djb2]

I did this recently, after practicing first on a few boneyard cars.

I needed to practice since my good tools and the Camry are on opposite coasts.

The winning solution was a 14mm six point medium-depth 1/2" drive socket paired with a 15" or more of extension so that you can get leverage under the car. Somewhere in the path you need a swivel/u-joint/wobble-joint. The socket I used was an impact with a swivel built in, but you can do this job without a socket that expensive.

Harbor Freight sells an extension bar with wobble ends, usually for just under $10. I used this with the swivel socket, which was sloppy but worked. Either one alone would work. I also used a Harbor Freight 1/2" click torque wrench ($12), which I keep in the Camry mostly for the lug nuts. I have about 5 of these scattered about -- they are great value. You are less likely to round nuts when you have big bar than a short ratchet as you can more easily avoid off-axis force.

I didn't need heat on any of the practice cars or the actual one, but a few of the nuts felt close to needing it. I've learned that heating to red or orange is much more likely to work than using PB Blaster. But if you don't have a torch (propane is OK, MAPP is better) handy, PB Blaster or equivalent is better than nothing.

Alway use a 6 point socket, and always give up before rounding the nut. If you don't follow this advice, Sears sells a Bolt-Out set that has saved me a few times with exhaust nuts. If you go the bolt-out path, also use heat.