What's the best way to loosen up an exhaust bolt?

[MADMarc]

Okay okay, I've read these threads on other forums but want it here! ...and I can't remember. I have heard ATF, PB blaster and even WD40...what else is there and what works the best? I'm having a bitch of a time getting some exhaust bolts loosened up right now.

[Ninja Performance]

PB blaster. If quick doesn't work, blast and let sit over night. If that don't work, get out the hot wrench.

-Chris

[vr4gto]

PB blaster. If quick doesn't work, blast and let sit over night. If that don't work, get out the hot wrench.

-Chris

+1. But I'd save the time and go right for the fire.

[MADMarc]

Looks like I might need to head to the store again

[RealMcCoy]

Yep, an actual penetrating oil like PB blaster, liquid wrench, or Zep 45 is best, WD40 isn't really up to the task...

I use Zep 45 just because I have a couple cases of it sitting on the shelf.

I usually don't have the luxury of letting it sit overnight, can't tie up a bay that long when the job needs to get done... I soak them down with penetrating oil, then start warming it up with a propane torch, once it's good and hot, I'll let it cool slightly, then start spraying it down again(quenching) with penetrant. If it's still too hot it will just puff smoke, but it it's the right temp, it will sizzle and smoke a little, but quench pretty quickly.(and wick the oil into the threads) Then if it's a flanged nut or bolt, (like a turbo nut) I'll set an impact socket on it and give it a couple good whacks with a hammer. (that helps relieve the tension on the threads) then I usually hit it with the impact gun to remove.

Sounds kinda complex, but I seldom break studs and bolts anymore doing it that way, and THAT saves me untold amounts of time...

[MADMarc]

Well damn, I wish I had a propane torch :( This is awesome info. Unfortunately for me I am waiting on a new tcase but that does give me the time I need to soak it like mad. Going to soak it in PB tomorrow while I redo the brake calipers and see if I have any luck towards the end of the day. Thanks! :)

[marshallh]

I struggled a lot with this. I also had to drill out the bolts on the original downpipe/cat. I soaked them in pb blaster 2 days straight, and no dice even with impact.

Drill out starting with a very small bit and work your way up, use wd40 to keep the bit from getting too hot.
I tried to use an easy out, but it turned out I didn't need it. These are the remains of the cat bolts:

http://img219.imageshack.us/img219/8193/img2429p.jpg

Had to use a torch to get the O2 sensor out of the bung. Heat bung red hot, unscrew sensor a few turns, heat again, etc.

[IPD]

PRODUCTS (http://www.bernzomatic.com/PRODUCTS/KITS/TORCHKITS/tabid/215/ctl/Detail/mid/1147/xmid/6936/xmfid/3/Default.aspx)

say hello to your new best friend.

[MADMarc]

Ouch, Marshall! Hopefully I can get them out...hoooopefully. how much do those torches run? I'm on my phone or I would just open a new tab and figure it out.

[92pearltt]

nuke them with a torch and melt candle wax in there. Don't think it works? I just got my exhaust studs out of my cat from my 91 stealth. Came out with zero problem after heating and putting the wax in there.

[Ninja Performance]

Normally the "Hot Wrench" isn't referring to a small propane torch. It's the Oxy Acetylene ;) That gets it dun!

-Chris

[DrGonzo]

LOL... yeah a propane torch might get it hot, but nothing compared to an Oxy Acetylene torch. I don't think that propane torch will even be worth paying the money for. The point of the heat it to get it red hot so it breaks away as the metal shrinks. Propane torch is not going to get the metal hot enough to shrink it.

[MADMarc]

I was wondering how long I would have to stand there w/a propane torch to get it glowing lol oxy acetylene is definitely out of my budget :(

[IPD]

propane still works. it may take a bit longer, but it does work. shooter & i used a propane torch to un-fuck the bolts on my mudflaps.

[MADMarc]

Well, just an update, pb blaster already loosened up 3 of the 5 bolts that I need to get...one seems like it's almost there and one more I am still worried it will break. I'm REALLY hoping this stuff can saturate into the bolt over night. I will probably put it on 3 more times before I knock out in a while. The can says to saturate, then knock the bolts, resaturate and repeat until it loosens up. Does this sound about right?

[speedy25]

As a long time veteran of the rust belt, you CANT work on cars without oxy/acetylene torch. Propane does NOT have the heat necessary to expand fasteners enough to move them. Yes of course SOMEONE has managed to get a job done with propane somewhere. Penetrants are useful for fasteners that initially move but you may have the fastener break if you dont have some sort of lube to keep it from seizing as you try to run a bolt out with more rusty crud on the end to keep it from turning.

Make friends with someone who has a torch. It will save you a LOT of time and headaches.

-SP

[IPD]

As a long time veteran of the rust belt, you CANT work on cars without oxy/acetylene torch. Propane does NOT have the heat necessary to expand fasteners enough to move them. Yes of course SOMEONE has managed to get a job done with propane somewhere. Penetrants are useful for fasteners that initially move but you may have the fastener break if you dont have some sort of lube to keep it from seizing as you try to run a bolt out with more rusty crud on the end to keep it from turning.

Make friends with someone who has a torch. It will save you a LOT of time and headaches.

-SP

i favor using both penetrants and a torch.

[RealMcCoy]

As a long time veteran of the rust belt, you CANT work on cars without oxy/acetylene torch. Propane does NOT have the heat necessary to expand fasteners enough to move them. Yes of course SOMEONE has managed to get a job done with propane somewhere. Penetrants are useful for fasteners that initially move but you may have the fastener break if you dont have some sort of lube to keep it from seizing as you try to run a bolt out with more rusty crud on the end to keep it from turning.

Make friends with someone who has a torch. It will save you a LOT of time and headaches.

-SP

I seldom see rust belt cars here. Every time I have, I've sworn to find a new profession if I had to work on them on a daily basis. We are talking about a very different process. My use of the propane torch is primarily to wick the lube into the threads. It makes plenty of heat for that purpose. I have had to break out the Oxy/Acetylene torch periodically, but at that point we're often beyond the help of penetrating oil...

[marshallh]

If you don't have access to an acetylene rig, you can buy some mapp gas and put it on your torch instead of propane. It burns a LOT hotter, close to acetylene.

But then you may end up needing that cutting torch + rig anyway :)

[MADMarc]

Still cant crack the bolt :( Looks like I might just break the damned thing and replace it w/a new bolt. Fortunately, though, it is a bolt and not a stud...at least that's working for me right now :/

[BigTyla]

An impact wrench has never failed me. Then again, all the cars I've worked on have been from the South.

[MADMarc]

Broke the damned thing off...soaking didn't work now I need to drill it :( BOO!