Removing exhaust manifold bolts

[sapratt]

Can anybody tell me how to remove exhaust manifold bolts with out breaking them?
I need to replace the head gasket and I'm having a hard time with the exhaust maniflod bolts.

 

[tubbster]

6 point and torque.
It sucks when you break them. Then you have to weld a nut on 'em. The welding often loosens them up enough to walk out by hand though.

 

[sapratt]

Thanks I'll give that a try. Everything went well until I got to the manifold bolts.

 

[burnham]

I've jacked up the exhaust on a front wheel drive 4cyl before so I didn't have to remove the manifold bolts. Lift out the old gasket and tuck the newone in. It was on a car I didn't care about much, though.

If you break the bolt head off you can grind the leftover stud flat, hold a nut up to it, and weld the nut to the stud (welding the inside of the nut). While it's still red hot back it out. It's a lot easier than trying to drill something out of the head.

 

[EatenByLimestone]

I let them soak a few days with PB blaster. I resoaked them every day. I was extremely worried about them also since they had been on since '91. (I had to pull them last winter.) Surprisingly they came off without any problems. If they don't want to come off easily, I'd play heat over it to get the penetrating oil to soak a little further down into it.

Matt

 

[struggle]

Are you removing it from the head? Is there a way you can pull the head off with just unbolting the exhaust flange? THen you could take an impact wrench to take them out or just leave the manifold on the head if you do not have to service the head beyond the gasket.

What kind of vehicle?

 

[Wrigley]

Definitely agree with the soaking first -- PB is good, Kroil is better if you can find it. Ultimately if that won't do it, the old "heat wrench", gently heating with a torch, will prevent snapping off a bolt. But be very careful with the torch -- heat, flame and fuel are a bad combination. Put some anti-seize on the bolts during reassembly -- you never know if this will need to be disassembled again.

 

[sapratt]

I soaked them in pb blaster. But not for a few days.

 

[Cluttermagnet]

Definitely agree with the soaking first -- PB is good, Kroil is better if you can find it.

Bingo! Kroil is very good, hard to beat IMO. Spray it repeatedly for a day or more, give it time to soak in. Kroil is available only factory direct, I believe. Kano Labs, Nashville, TN. Look it up on the net. They can sell you a small quantity in spray cans inexpensively. BTW get some of their literature and read some of the testimonials about Kroil. Very interesting. Spray, wait, spray. With patience, you will loosen bolts you thought sure you'd be breaking.

Disclaimer: I have no financial connection to Kano Labs. Just a satisfied customer.

http://www.kanolabs.com/

Look at Aerokroil (spray cans of Kroil)
They promise next day shipping of trial size order.
Liquid Kroil in an oiler can is good, too.

Their order form now requires that you supply a company name. That's something I'd not encountered before, but I do have a company name.

 

[Beanscoot]

What engine?

 

[Dune]

I've jacked up the exhaust on a front wheel drive 4cyl before so I didn't have to remove the manifold bolts. Lift out the old gasket and tuck the newone in. It was on a car I didn't care about much, though.

If you break the bolt head off you can grind the leftover stud flat, hold a nut up to it, and weld the nut to the stud (welding the inside of the nut). While it's still red hot back it out. It's a lot easier than trying to drill something out of the head.

Sorry to contradict your otherwise good advice, but the welded area should be allowed to cool completely before being removed. First, a red hot bolt is soft, therefore weak, and second, the hot bolt has expanded, after cooling, it will have shrunk, and be much more likely to come out without breaking. If one were removing a nut rather than a bolt, the oposite would be true.

 

[gpcollen1]

Kroil is old school and good - BUT - PB Blaster is the best stuff out there. Soak them as often as possible and tap the stud. It may take a day or it may take a week. You could always just snap the nuts off, drill out the studs and replace them, right? And if it is too tough for you, have a machine shop do it and recondition the head while you are at it.

 

[burnham]

I've jacked up the exhaust on a front wheel drive 4cyl before so I didn't have to remove the manifold bolts. Lift out the old gasket and tuck the newone in. It was on a car I didn't care about much, though.

If you break the bolt head off you can grind the leftover stud flat, hold a nut up to it, and weld the nut to the stud (welding the inside of the nut). While it's still red hot back it out. It's a lot easier than trying to drill something out of the head.

Sorry to contradict your otherwise good advice, but the welded area should be allowed to cool completely before being removed. First, a red hot bolt is soft, therefore weak, and second, the hot bolt has expanded, after cooling, it will have shrunk, and be much more likely to come out without breaking. If one were removing a nut rather than a bolt, the oposite would be true.

Yeah, I understand what you are saying.....but having tried it both ways I've had better results winding the bolt out while it's still hot. :gulp:

 

[Dune]

Indeed, to each his own.

 

[jdemaris]

Can anybody tell me how to remove exhaust manifold bolts with out breaking them?
I need to replace the head gasket and I'm having a hard time with the exhaust maniflod bolts.

There IS no sure way to do it. All depends on many factors, including the alloy of the studs and nuts. Heat the nuts unitl orange red and then douse with cool water. Most will come loose after that's done a few times. But, some get broken no matter what you do. Sometimes the safeest bet is to cut the nuts off the studs - either with a torch or a nut-breaker. Than, retap the threads on the stud if there's enough metal left.

In regard to liquid remedies, e.g. PB Blasler, etc. ? From what I've experienced with 40 years as a diesel mechanic , none work - it's mostly hype and wishful thinking. Many times, I've experimented with groups of bolts and nuts all aged and rusted the same. Sprayed a few for many days and left the others dry. If they came off without breaking - they ALL came off including the ones I didn't spray at all. If they broke, they all broke.

Hey, if people out there believe that stuff does anything - so ahead. I ran a large John Deere contruction repair shop for years, and if we could have found anything that even worked a little, we'd gladly have bought it. And, we tried many. Now, preventitive maintenance by assembling with Never Seiz or equivalent -does work very well.

 

[Dune]

Can anybody tell me how to remove exhaust manifold bolts with out breaking them?
I need to replace the head gasket and I'm having a hard time with the exhaust maniflod bolts.

There IS no sure way to do it. All depends on many factors, including the alloy of the studs and nuts. Heat the nuts unitl orange red and then douse with cool water. Most will come loose after that's done a few times. But, some get broken no matter what you do. Sometimes the safeest bet is to cut the nuts off the studs - either with a torch or a nut-breaker. Than, retap the threads on the stud if there's enough metal left.

In regard to liquid remedies, e.g. PB Blasler, etc. ? From what I've experienced with 40 years as a diesel mechanic , none work - it's mostly hype and wishful thinking. Many times, I've experimented with groups of bolts and nuts all aged and rusted the same. Sprayed a few for many days and left the others dry. If they came off without breaking - they ALL came off including the ones I didn't spray at all. If they broke, they all broke.

Hey, if people out there believe that stuff does anything - so ahead. I ran a large John Deere contruction repair shop for years, and if we could have found anything that even worked a little, we'd gladly have bought it. And, we tried many. Now, preventitive maintenance by assembling with Never Seiz or equivalent -does work very well.

Did you try gently tapping on the stuck object after soaking with oil? Thats a hard sell you are trying to make there.

 

[TMonter]

Do you have an impact wrench? That will work well on exhaust bolts much of the time.

 

[EatenByLimestone]

Do you have an impact wrench? That will work well on exhaust bolts much of the time.

+1

One of the best purchases I've made for working on cars and trucks was an electric impact wrench. I don't know if he would have the room to use one to get at an exhaust mainfold though. Cars seem to be made with smaller and smaller engine compartments.

Matt

 

[Cluttermagnet]

Hey, if people out there believe that stuff does anything - so ahead. I ran a large John Deere contruction repair shop for years, and if we could have found anything that even worked a little, we'd gladly have bought it. And, we tried many. Now, preventitive maintenance by assembling with Never Seiz or equivalent -does work very well.

Never Seize is great stuff. I wish they would use that at the factory. It would indeed make life a heck of a lot easier for all of us.

 

[jdemaris]

Did you try gently tapping on the stuck object after soaking with oil? Thats a hard sell you are trying to make there.

Is that a serious question? Our number one problem when working with bulldozer and escavator undercarriage parts was the removal of stuck/broken bolts,studs and nuts. Been doing it for 40 years and I've either tried, or witnessed others trying, just about every remedy humanly possible including chemical, heat, and shock treatment.


And, exactly WHAT is it that you think I've presented as a hard sell? I've presented what I have experienced, that's all.

 

[Dune]

Are you serious that no type of penetrating oil helps in any way? Thats a hard sell to me anyway. You are not the only one with many years of experience.

 

[Beanscoot]

One thing that I've noticed the penetrating oil clearly help is a bolt that can just be moved, if it gets the spray then one can turn it back and forth and the oil will greatly assist in turning the rust into oily mush.

 

[EatenByLimestone]

So did you get the bolts off? Please update us before the thread gets locked over people argueing over the merits of penetrating oil!

Matt

 

[jdemaris]

Are you serious that no type of penetrating oil helps in any way? Thats a hard sell to me anyway. You are not the only one with many years of experience.

I didn't claim I was the only one- not even close. I may, however, be the only one on this forum that has experimented with rusted/broken studs, bolts, nuts, etc. - with non-treated versus treated, laid side-by-side. For anybody that simply sprays a stuck fastener with a brand-name penetrant, then gets it off a day or so later . . . they have no idea if it actually got better, or would of come off anyway. I have found that those that do come off a little better, worked just as well when hit with conventional motor oil or - sometimes - just warm water.

If someone on this forum has actually done some testing - that's fine with me. I'm telling you want I've found - and it was, and still is a major issue with many repairs and restorations I do.

So, you mention there are others? Good. I'd like to hear about remedies that are actually known to have worked - and if so - what environment and what types of alloys were involved. Brass on steel, stainless on non-stainless, alloy steel on alloy steel, steel stud in aluminum, high-heat areas, etc. They all act differently, especially in an acid-environment created by road-salt and even more especially when two disimilar metals are involved.

 

[Gooserider]

A couple of things I have found that haven't been mentioned - I would agree (albeit w/o having tested) that lube oils and other magic potions don't seem to do much for breaking something loose, but once you can get a half turn or so, they do seem to help if you work the nut (or bolt) back and forth as you take it out. Don't just crank the bolt out in one go however; instead treat it like you were using a tap - crank out 3/4 turn, in 1/4, or some variation. The idea is to give a chance to clear out any rust or corrosion crud.

Second, If you had a battle, throw the old fasteners away and replace them, especially if it is a measured torque assembly - the torque numbers are based on CLEAN, NEW threads, that rusty old bolt will probably give you a false reading.

Third, if you have several bolts holding a part down, DON'T try to pull any of the bolts out completely until ALL the bolts have been broken free - do it in a pattern just like putting on a head - 1/4 turn at a time. It can even help to tighten the other bolts back down to get the last one loose... The distortion and gasket expansion you get from taking one bolt out can increase the tension on the remaining ones. Once you have all the bolts out by a turn or so, you can stop worrying about this and start pulling them out one at a time.

Gooserider