Loosening rusted nuts with Acetylene torch?

[monteperformance]

I have some heavily rusted nuts on an exhaust system that will need to be removed soon. I have an acetylene torch which I have never used. Will that be hot enough to loosen them? Or do I need the Oxygen-Acetylene setup?

 

[Professur]

What part of the system? With the exception of manifold bolts, exhaust bolts are usually just burned off and replaced.

 

[SgtRauksauff]

is the car in running condition, and being driven?

After a drive, put some penetrating oil on the nuts. do this for a few days. if you've got the time.

if you don't have the time, use a torch to heat'em up, then put the penetrating oil on. (I use PB blaster, but Kroil is good too. WD-40, not so much.) Get'em cherry red, then when they're still hot but not glowing, use the oil. be careful of starting a fire.

Or, since it's an exhaust system, just use a Sawzall!!

--sarge

 

[shotgunfatcat]

Or, since it's an exhaust system, just use a Sawzall!!

--sarge

+1

I would cut em off and replace them with a sawzall or cut-off wheel.

 

[george4]

Just did this. 89 corvette, never had removed exhaust from manifold. Tried penetrating oil and let soak over night, no love. Used O/A with a small tip. Had a friend adjust the flame while I was under the car getting in position. Hands me the torch, get the nut dull red, hand him back the torch and get a socket on there quick. Had to do this with all 6 nuts. Did not break a stud. All is well. Be careful with that flame.

 

[djd99]

I have some heavily rusted nuts on an exhaust system that will need to be removed soon. I have an acetylene torch which I have never used. Will that be hot enough to loosen them? Or do I need the Oxygen-Acetylene setup?

If you don't want to take the easy route by cutting it off use your Acetylene torch and get the nut red hot and back it out with a impact. Usually the torch is just as fast.

 

[Warrenator]

Heat it with a torch, apply a candle to the exposed theads, wax melts into the rusty bolts and helps loosen.

 

[monteperformance]

Thanks for the replies. It is a running car & I am looking to change the exhaust from the cat-back. The rusted nuts in question are attaching the exhaust to the cat (studs on a flange). I suppose I could always just get a new cat, but figured I'd try to remove the nuts without breaking or cutting.

Here is a pic of exactly what I'm talking about, except in this case it looks like they were using oxy/acetylene, which I know is hotter.

 

[Professur]

If you break the stud, jsut drill it out and replace it with a bolt .. no need to replace the cat for that.

 

[Dewaynep]

I am not sure how the 2 compare temperature wise, but I use a simple propane torch with MAPP gas. It's hotter than propane and does a fine job of heating bolts up to remove them. I have lots of experience with rusty bolts, I live in Western NY where road salt is heavily used.

 

[csp]

Personally I like to get the nut/bolt/stud hot and let it cool completely. The heat expands and cooling lets it contract, breaking the corrosion even more.

 

[Jack Olsen]

Kano Kroil has never let me down. Let it soak overnight.

 

[noid]

Just use/buy a nut splitter and break off the nuts and put new ones on.

 

[folgers]

Get the bolt red hot then douse it with water the rapid expansion then shrinkage will crack it loose. After that you can spray some oil on it to make turn easier.

 

[Kevin54]

Thanks for the replies. It is a running car & I am looking to change the exhaust from the cat-back. The rusted nuts in question are attaching the exhaust to the cat (studs on a flange). I suppose I could always just get a new cat, but figured I'd try to remove the nuts without breaking or cutting.

Here is a pic of exactly what I'm talking about, except in this case it looks like they were using oxy/acetylene, which I know is hotter.

That's a cutting torch they are using.

Heat them red hot and get a socket on it. Turn it both ways though instead of just horsing it off in one direction to break the rust loose.

 

[isaac338]

Just cut the nut off, then heat the flange and back the stud out with some vise grips.

 

[tdkkart]

Most of the time I don't even screw with trying to save this stuff, just put a 6 point socket on it with a breaker bar and twist the nut off by tightening it till it snaps. If it's on a stud just twist it off, drill out the stud and replace with a bolt.

 

[nate379]

Roughly 1/2 the temp. 6000* vs about 3500*. Propane is about 2300*

I am not sure how the 2 compare temperature wise, but I use a simple propane torch with MAPP gas. It's hotter than propane and does a fine job of heating bolts up to remove them. I have lots of experience with rusty bolts, I live in Western NY where road salt is heavily used.

 

[turrican]

If the nuts you're trying to remove are about as, or less rusty than the ones in the previous picture, you should be able to back them off using only MAPP gas. BUT, get them good and hot, let it sit on them for a good minute or more. If you have oxy/acetylene then you probably only need to lick them for 5-10 seconds.

If they're considerably rustier - meaning mainly that the nut sides or stud threads are deteriorated - you can try the same thing but using reverse-fluted "twist" sockets to back the nut off.

If they're so rusty they look like some sort of rusty peg sticking out - go nuts-up and just torch 'em off with the o/a

In any case I almost always back them off by hand, not impact - that way you can feel if it starts binding, hit it with more torch, etc. Though again, if they're like the ones in the pic (which really aren't too bad), a little heat and judicious impact should work fine.

 

[Lugnut64052]

I never touch exhaust fasteners without heating them up first.

Yes, the picture shows a cutting head, but it'll heat up a bolt head (or a nut) fine. Just don't hit the cutting trigger while you're heating. You can actually get a more pin-point heat with a cutting head. You're not spraying a flame all over the place in case you have sensitive parts nearby (like oxygen sensor wires, etc, etc)

What I do-- fire up the torch, turn the fastener red (or even yellow), calmly shut the torch off, then remove the fastener. I gun them off with an impact, but you can use a rachet or wrench too. I guarantee that if you get them yellow, they'll come off every time, and easily too.

I've successfully removed bolts and nuts that looked way past save-able. The heat knocks all the rust and scale off and they don't look nearly as weathered afterward. If there is simply nothing left of the fastener, just cut it off with the cutting head and replace.

Edit-- you need an oxy-acetylene setup to do this.

 

[regguy1]

Kano Kroil has never let me down. Let it soak overnight.

Jack,
If you lived in the "rust belt" you might've been let down a few times.
I've bought a few cars that lived in CA all their lives..and man, what a difference

True story:
A guy I know was on vacation in CA and his transmission went out, he took it in for repairs and when they lifted it up an looked underneath...the mechanic said to him "where the hell has this car been.....on the bottom of the ocean?"

 

[Jack Olsen]

True. It's pretty benign out here compared to where I grew up (Chicago). Freeze cycles and salt will do a job that's hard for us Californians to comprehend.

But the latest Kroil success was getting the exhaust off of an engine that had headers and mufflers dating back to 1995 -- in Ontario, Canada the whole time.

 

[turrican]

Jack,
If you lived in the "rust belt" you might've been let down a few times.
I've bought a few cars that lived in CA all their lives..and man, what a difference

True story:
A guy I know was on vacation in CA and his transmission went out, he took it in for repairs and when they lifted it up an looked underneath...the mechanic said to him "where the hell has this car been.....on the bottom of the ocean?"

I've worked at dealerships on both coasts (first in Los Angeles, now in Boston). You're not kidding, it's a WORLD of difference.

There are cars that come in at the Boston shop that I (now) think "wow, this one's in GREAT shape" that would be "HOLY ****, guys, come look at THIS rustbucket!" in Los Angeles.

I never even had to use heat until I moved out here

 

[3bay]

Get the bolt red hot then douse it with water the rapid expansion then shrinkage will crack it loose. After that you can spray some oil on it to make turn easier.

Thats how I've done it for 35+ years.

You can also try PB Blaster, its the best thing I've used for rusty things.

 

[nate379]

My 03 WRX came from Cali and I was able to pull off teh whole exhaust system with just a 3/8" ratchet and wrench not long ago.

A YEAR in the rust belt and I would have had to cut it off.

 

[PAToyota]

Kano Kroil has never let me down. Let it soak overnight.

I'm a big believer in Kroil. Soak it a few days in a row with a little leverage applied each time, sometimes some heat, and it usually comes out with little effort.

Most of the time I don't even screw with trying to save this stuff, just put a 6 point socket on it with a breaker bar and twist the nut off by tightening it till it snaps. If it's on a stud just twist it off, drill out the stud and replace with a bolt.

But for exhaust work, this is what I do.

 

[ephotrod]

A torch a toilet bowl ring of wax (100% bees wax) and time will take any bolt off. Heat the bolt or offending fastener to a cherry red apply some wax and let it wick in to where the seizure is, let it cool (air cool) and then remove. This method has yet to fail me, and was taught to me by an old timer.
Josh

 

[Skin]

I've worked at dealerships on both coasts (first in Los Angeles, now in Boston). You're not kidding, it's a WORLD of difference.

There are cars that come in at the Boston shop that I (now) think "wow, this one's in GREAT shape" that would be "HOLY ****, guys, come look at THIS rustbucket!" in Los Angeles.

I never even had to use heat until I moved out here

hope you moved out here for money or a woman, cause it sure as hell wasnt for the weather.

 

[swharris]

Heat it with a torch, apply a candle to the exposed theads, wax melts into the rusty bolts and helps loosen.

Do THIS ^^^^! Works like a charm. You'll be shocked how easily they will come off.

 

[TexasT]

if you haven't found out yet those are nuts on studs. just get an impact on them. they either come out, round off or break off. easily drilled out once you have the pipe out of the way. Just be careful of the threads. If i remember right they are metric. if they do round off or break you can weld another nut on whats left and try again with the impact.

How is your project coming?

 

[sberry]

I would be lost working on cars/trucks without a torch and welder. I don't know how some people do it. I am not much for busting a bolt off if I can help it, very rarely and another rarity to drill one out, 95% of the time weld an attachment to it. Broken bolt/stud specialist, have removed thousands of them.

 

[strelnik]

Just did this. 89 corvette, never had removed exhaust from manifold. Tried penetrating oil and let soak over night, no love. Used O/A with a small tip. Had a friend adjust the flame while I was under the car getting in position. Hands me the torch, get the nut dull red, hand him back the torch and get a socket on there quick. Had to do this with all 6 nuts. Did not break a stud. All is well. Be careful with that flame.

Agreed.
I have removed nuts on exhaust systems which were last tightened in 1938. I got guidance. It's not hsard but requires care.

1. Spend 5 bucks and get a 0000 acetylene tip that will apply a small and very controllable HOT flame to each nut.

2. Raise the hood as high as possible. Work with a second party. Keep a fire extinguisher handy.

3. WEAR GOOD GLOVES so you don't accidentally burn yourself.

4. Get a deep socket or ratcheting wrench to loosen the nut after heating.

5. BEFORE heating, use a wire brush to clean the stud shaft BEFORE you touch the nut with the welder tip.

6. Get the nut RED HOT before you do anything. The expansion from heat will help you.

7. Let the nuts drop in a pan or on the floor and pick them up later with a MAGNET, so you don't accidentally touch them.

8. WORK SLOWLY.

Once they are off, stick them in cold water, then wire whenning a tap through them. Hold the nut with vise-grips when you run the tap through the nut.

Good luck!

 

[monteperformance]

Thanks for all of the info! I had a setback because I am dealing with transmission problems now, so the exhaust is on the back-burner. I'll be sure to update this thread when I do finally get to the exhaust.

 

[ersatzs2]

Thanks for all of the info! I had a setback because I am dealing with transmission problems now, so the exhaust is on the back-burner. I'll be sure to update this thread when I do finally get to the exhaust.

Whew, no pressure! All I can say, dude, is with all that advice if you don't report back with glowing success, you might consider not reporting back at all!

 

[DCarr]

I have heated up many rusted nuts with an Oxy / Acet. torch and never had a problem removing it after that. Worls great for studs in exhaust manifolds also.

 

[jay50]

I have heated up many rusted nuts with an Oxy / Acet. torch and never had a problem removing it after that. Worls great for studs in exhaust manifolds also.

Also comes in handy when you need a cig lighter....

 

[malibu101]

Also comes in handy when you need a cig lighter....

Now that's a real mans lighter!

 

[malibu101]

Agreed.
I got guidance. It's not hsard but requires care.

1. Spend 5 bucks and get a 0000 acetylene tip that will apply a small and very controllable HOT flame to each nut.

Good luck!

That is by far the biggest problems new guys to a torch have. They go at everything with a cutting tip. That size above is perfect for this type of work.
Get a hot flame in, heat the bolt/nut, and get out. Just blasting fire at it-Like a propane BBQ starter torch or a big tip on an oxy/act just heats up everything. Often destroying other things in it's wake.

 

[MScott]

Biggest thing I have noticed when using a torch on rusted nuts or bolts is that when you get the wrench or socket on it, keep turning until the nut is completely off. Stopping part way can cause the nut to seize on the threads.

 

[gbick]

Does this "heat treat" soften the socket? Would a thicker impact socket fair better than the thinner chrome ones? Hate to ruin my snap- on sockets.