How to remove bolts on exhaust pipe on van

(Zone 6b)

I am trying to remove some bolts and nuts on an exhaust pipe on my van and so far, no go.

I wondered if anyone has knowledge on this. I've been using aerokroil and have tried a propane torch. A lady on another thread advised against the propane torch because she had one explode on her and had severe burns.

I bought a coke to pour on it. Yesterday I tried candle wax.

I also have a compressor and an air wrench, but haven't tried it because I heard they can twist the bolt off, also I am new to air tools, they kind of scare me.

I need to get this done as soon as possible, but for me that might be months. In the meantime I do have another car to drive.

Thank you for any help,

Durhamville, NY(Zone 5b)

Are you talking about bolts and nuts that hold the exhaust to the exhaust manifold?

If it is a stud then breaking it off is a problem, if it's a bolt with a nut then it's not.

There are basically two approaches oil and/or heat. Oil it every day for a couple of weeks and then try it. By all means use the impact wrench. It is less likely to break a stud than a hard pull with a wrench. Most you can adjust the amount of power the produce. The biggest problem you might run into is rounding the nut off. If oil isn't doing it then try heat. I own oxyacetylene torches so if I could get wires and insulation away form the area I'd heat it red hot if it was a stud or cut it off if it was a bolt. You can try the propane torch. The one that "exploded" in her hand must have had a bad leak and most likely was being used in an enclosed space. If you are worried about a leak make up a soap and water solution and test the 3 places a torch can leak; where the head connects to the pipe, the connection between the pipe and the base, or where it screws onto the cylinder. A little common sense to not use a broken torch and you'll be fine.

If it's a bolt and nut you can try slipping a hacksaw blade between the manifold and exhaust flange and cut the bolt. Good luck, it tends to be a PIA job.

(Zone 6b)

Well thank you so much for your response.

Yes it's the pipe that attaches to the exhaust manifold and has the three nuts and bolts. I read something today online, and the man said he sprays 3 times a day for 3 days before he tries it. So I guess I'll try that. I can tell I am rounding off that one bolt and sure don't want to do that.

So you think it's okay for me to use the air impact wrench after the 3 days of spraying it with aerokroil?

That sounds like a plan. Again I appreciate your help.

I just wish I had a little more experience with the compresser.


West Pottsgrove, PA(Zone 6b)

While you're waiting for the kroil to do its thing, you could try out the air wrench on something else, just to get used to it.

(Zone 6b)

Like the neighbor's car? :D

Durhamville, NY(Zone 5b)

Since it is a bolt and nut you are going to have to hold either the bolt or nut. Take a box wrench and put it on the top so that as it moves it will run up against the manifold an stay in place. The advantage to an impact wrench is that the hammering that it does will loosen stuff that a steady twist won't six point and tight fitting sockets help with the rounding. If the socket you have fits the least bit loose try a metric or vice versa. To prevent further rounding you need a tight fit. If it won't loosen try tighten it. Once you get it to move you've got haft the battle licked. if you break the bolt you've won that one.

I take it you are trying to replace the gasket / donut inbetween. However you get the bolts out replace them with new ones. It will make your life much easier if you ever need to get them out again. We are talking less than a dollar for all three. They aren't any kind of grade bolt or anything special.

As far as the air impact (I'm assuming it's an impact and not an air rachet) is concerned they depend on their weight to do their job. They aren't inclined to jerk around like a drill will.

Tallahassee, FL

I have often used a cold chisel to cut the side of a nut, holding chisel parallel to bolt. There are also nut splitters, but I have never used one.

(Zone 6b)

Ok I sprayed off and on for 3 days.

Turned the compresser on, got the impact wrench and right sized socket.

Tried 2 of the 3 nuts, and it didn't loosen them.

What now?

More spraying? more waiting? Whack them with a hammer?


Rocky Mount, VA(Zone 7a)

Light - you do have a sense of humor that I can enjoy.

Unfortunately, exhaust systems are not very easy to work on. The heat from the exhaust causes the metal to corrode faster than most metal does and after a few years of this corrosion not many "standard" methods work to separate the metal parts, which by this time are "rusted" together.

You are going to have to get "tough" with it and destroy some of the parts you are taking apart, but that is really ok, because they needed to be replaced anyways. A good hand held grinder comes in handy at a time like this. The hardware is cheap to replace in comparison with the vehicle.

And be cautious with the grinder, we can replace the hardware much faster than the skin and bone of ourselves.

This message was edited Jul 1, 2008 2:51 PM

Rocky Mount, VA(Zone 7a)

Oh yea, if it is a stud rather than a bolt try not to damage it you will make work for yourself.

Durhamville, NY(Zone 5b)

You didn't say what kind of van and engine so how much space do you have to work. I didn't say it before but if you have to us an extention on the impact use as short an extension as you can because it seriously reduces the impact. Don't be afraid to let the impact wrench hammer away for awhile because sometimes that will work. The other thing I'd try to do is to tighten the nuts. Sometimes nuts will tighten when they won't loosen. How are you holding the heads of the bolts.

Since they are bolts and nuts what I would do is this.

I'm going to assume that the bolt head is on top by the manifold and the nuts are on the bottom. Take you box wrench, put it on the bolt head and jam it up against he manifold so that you don't have to hang onto it. On the bolt end put a 6 point socket on and a extension long enough so that you can get you drive in the open where you can put a pipe on it. As long as you don't round the nut or bolt off what you are going to do here is either turn the nut or break the bolt. With about 2 feet of extension on a breaker bar or rachet you are going to either turn the nut or break something. The something you are trying to break is the bolt. A good set of half inch drive tools should take a pipe without a problem. If you break one of the tools hopefully it is something with a lifetime warranty. Wear gloves, your knuckles will find something sharp when it all lets loose.

I know you said this is a bolt and nut but incase we mean different things by that a bolt and nut will have a head and a nut. A stud will have just a nut and the other end screws into the manifold. If it is a stud disregard the above advice about breaking it. The last thing you want to do is break a stud.

(Zone 6b)

Ok I took some pictures.

Thumbnail by Light_for_Jesus
(Zone 6b)

The van is a 97 Chevy Astro.

Here is a side view.

Thumbnail by Light_for_Jesus
(Zone 6b)

The compressor is a 21 gallon one and it is getting about 100 psi when I turn it on.

Here is the Impact wrench. It is a 15 mm socket.

I do appreciate your help.


Thumbnail by Light_for_Jesus
Rocky Mount, VA(Zone 7a)

Light, there does not seem to be an appreciative amount of rust on those bolts. Have you ever heard the saying "give me a lever and I'll move the world"? Set the air wench aside get a "breaker bar" (a solid piece that the socket will fit). if you cannot break it loose with that, get a long piece of pipe to go over it for more leverage.

Durhamville, NY(Zone 5b)

I agree with Dyson. It doesn't look that badly rusted. From what I can tell about your impact wrench it looks like a 3/8' drive with a short extension. Extensions severely reduce their effectiveness. A 3/8" drive impact likely doesn't have enough torque to loosen the nuts.

As Dyson wrote get a breaker bar or good rachet and an extension and a pipe. The extension needs to be long enough to bring the breaker bar low enough so that you can put the pipe on it and still be able to turn it. That should get the two nuts to the right of the picture from underneath. The last one you may have to reach from the side. You are going to have to hold the head of the breaker bar with one hand and push on the pipe with the other. If you still can't turn it get back here and I'll give you more suggestions.

Since it looks like you have the tire off I hope you have the van well blocked up before you crawl under it.

For a final question why do you have to take this pipe off anyway.

(Zone 6b)

Thanks Dyson and Doug,

I recently bought a breaker bar, but it is only about a foot long. I put a pipe over the end, I learned that recently in taking the tire off. A man at the hardware store told me what to do and it worked. It was a breeze. After I had struggled all day with the lug nuts. So simple once you know how and have the correct tool.

However, I tried it today with the breaker bar and pipe on these, and so far I haven't been able to get it to move. I thought it moved, but I guess it was just slipping. I seem to be rounding off nut so I stopped.

Ok, so one answer might be getting a 1/2 15 mm socket for the air wrench.

Saw this tool on ebay today, called Tite Grip. Wondered what you would think of it.

Also saw some called Nut Crackers or Nut Splitters. What about those?

Thanks again for your help.


Durhamville, NY(Zone 5b)

I've never had great success with nut crackers. In addition in this particular case I don't think you have enough space and the washer surface that is part of the nut will totally frustrate a nut cracker.

I've never used a Tite Grip but I think that most places will have something similar

You have found out why exhaust systems are evil things to work on.

What I think you are dealing with is nuts that were way over tightened.
If it was in my yard I'd heat the nuts red hot with a oxy-acetylene welding torch and then I could just about unscrew them with a socket and my fingers. I hesitate to tell you to use your propane torch without knowing exactly where all the wiring and other lines run on the engine because that sort of torch spreads a lot of heat around and I not even sure it will heat them hot enough.

With that said are you using a 6 point socket? Are you sure the nuts are 15mm or could it be 9/16? 6 point sockets are much less likely to round a nut off and one may grip a nut that has already started to round off. If the 15mm socket is a little loose you maybe able to pound a 9/16" socket on to the nut with a hammer. You may damage to socket enough not to be able to use it again. There is also a socket that that has sharp flutes inside to remove a rounded off nut but in your case I suspect that the nut is so tight that it will only round the nut off more

If those ideas don't work then I think you are down to cutting the nut off which can be a supreme PIA depending on how much space and what tools you have.

Aransas Pass, TX

Karen, I live on the Tx coast where everything rusts 24/7. If you a have tried the sprays get some motor oil used or new either squirt it or coat a rag and let the entire part soak not just the studs. It should all turn a dark color when it is saturated. The part needs to have oil dripping off it to break the surface tension. It is rusted inside and has been heated and cooled. I hate exhaust parts you may have to hammer on a socket that is undersized along with a 4' piece of pipe. Make sure the socket is not a long one as you want to center your turning directly to the nut. Anything off to the side will try to strip the nut.

It looks as if 2 of the 3 nuts are easy to get too except the top left. I do not think a socket will fit ? If you have time on your side I would just soak it real good for a few days. The metal will absorb oil for quite a while. Sometimes things come apart real easy after an oil soak. I keep a squirt gun and my old oil. Mobil One it works wonders on rusty stuff.

If it was me I would just take it to someone who has the proper tools. What is tough for some people is easy for a experienced mechanic. They might only charge you $ 30.00 parts and labor. Now if you soak it in oil nobody will want to put a torch on it. Propane will not do the job and even with a cutting rig they still might snap.

Good luck. Oil,oil and more oil if you do it yourself.

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