exhaust manifold bolt is rounded off

Put my engine on an engine stand to rebuild it. One of the 9/16" exhaust manifold bolts wouldn't budge. Got out the breaker bar. Applied too much leverage and the head bolt is now rounded off. Thought about cutting the bolt's head off with a dremel tool cutting disc. Then, removing the exhaust manifold and clamping vise grips on it and unbolting it. Or, would it be better to stick weld a 5/8" bolt to it and proceed from there. Need advice. I'm afraid the bolt might snap flush at the block.

 

stick a nut on it and weld the center when it cools back it out

 

Are you using a six point socket ?
Put heat on manifold ( propane torch at least )

 

Is't Sears-Craftsman marketing a set of sockets made just for rounded off bolts/nuts? If you don't have access to a welder, you might try that first, along with some heat from a propane type of torch. Butch/56sedandelivery.

 

cut it off, (torch) slide manifold off, pipe wrench or vise grips... POC (pcs of cake.)

 

I'd try to weld a nut on it first, then shoot the bolt and manifold with PD Blaster or your favorite penetrating oil. While it's still warm, whack the end of the bolt with a hammer a time or two, then using a six point socket, try to loosen it a bit, then tighten it a bit, then loosen a bit, etc. Every once in a while, whack the end with a hammer again, it will help break the rust loose. As it starts to come out, lube it real good and run it back in a bit, then out.

It may take a while, but most of the time the bolt will come out.

 

I'd center punch drill the center. Step up drill sizes and pop the head off. Remove the manifold. Heat the bolt and try to remove it with vise grips. Are as said before weld a nut too it.

 

Try a metric socket..

 

I'd be for cutting the head off and sliding the manifold off. The bolt is toast anyway so take the easy way out. Get the manifold off where you can soak the threads for a while before backing it out with vise grips. With the manifold off you can see what's happening with the bolt.

 

For what it"s worth, it's prob rusted in the manifold not the head. Welding a nut on will not help. Cut the head off heat the manifold if you can. Then slide it off. If not cut the bolt at the head, then unscrew the remaining piece of bolt out. You might need a new manifold.

 

Lobo Crud & old olds have it right. better to use a cutoff disc now on the head of that bolt and get the manifold outta the way. Then you've go the whole length of the bolt to work with, not just what's left from where the bolt twists off again.

 

Don't use a pair of vise grips on the remaining piece of the bolt. Purchase a stud removal tool (all name brand tool mfrs offer one). They are specifically designed for the problem you're dealing with. Be sure to soak the threads thoroughly for a few hours at least, before you use the stud puller.

 

Yes go buy a tool for a one time job that will do the same thing as those vice grips you already have in your drawer.

 

Do as others have said, cut the head off, slide the manifold off. Then get some common paraffin wax and heat the area with the now headless bolt, hold the bar of wax near the part going into the block and let it run in around the threads. When cool you should be able to get it out easily. This is what the guys in the rebuild shop use.

 

soak it with penetrant first overnight and then try a metric socket with some heat. Impact wrench would help plus keeping your fingers crossed.

 

Yeah, do this and then when the bolt twists off flush with head surface you have considerably shortened your list of possible removal methods!!!!!!!!!!

 

Welding a nut on the existing bolt head will heat up the stud which will help loosen it up, use penetrating oil of your choice -- If it doesn't come loose on the first try heat it (the bolt head) red hot and let it cool again, sometimes it won't break loose on the first time (at least for me) I doubt that a propane torch will do much more than warm your hands, but if that is all you have, that's what you will have to use. Good luck!!

 

I have an oxy/acetylene torch and ac/dc stick welder, and ready for the task. Just need a good strategy. Thank you for the suggestions.

 

If you have a torch and stick welder heat up the head of the bolt then weld a nut to it when it cools it will shrink and will come out.

 

Another vote for cut the head off and weld a nut on when you get the manifold off. I tried to weld to a rounded off head on an exhaust manifold and ended up cracking the manifold.

Ryland

 

I agree with the cutting first, remove manifold, heat later and vise grip.

Multiply this 16 times if it's a 5.4L or 4.6L Ford, lol.

 

Yep, cut or drill the head off, weld a nut to the stub, and back it out.

 

From the picture, it barely looks rounded off. Were you using a 12 point socket? Use a 6 point, or pound a 6 point snug fitting metric on there and take it off. Do all this after soaking it with a 50/50 mixture of atf and acetone for a day or so.

 

Guess I should have looked at the picture, I wouldn't cut that off yet. Beyond a 6 point you could also try hammering a 14mm 6 point on. I find with bolts that are rounded or reduced in size due to rust you can often find a metric socket that will fit with a little persuasion.

 

if it was mine i'd take a piece of 1/8"x3/4" flat bar about 6" long and drill a 1/2" hole at one end, then i would plug weld it to the head of the bolt so the flat bar was at 12:00, let it cool and then try to move it, just wiggle wiggle, slowly slowly, if it comes loose then bend the flat bar straight out and use it to back the bolt out.

 

I,m with BobF post #14 but do several cycles of heat and wax before trying to brake it lose iv'e had my best lock with this method good luck

 

I would try this first. I would cut the head of the bolt as a last resort.

 

I have had good luck taking a 2 pound hammer and hitting the bolt sqaure on the head a few times.This will mushroom the head so a 6 point socket will hold and send a shock down the bolt to break loose rust.

 

yep, there is more than one way to skin a cat,, but the cat won't like any of 'em !!

Go for it, get-er-done.

 

As 56SedanDelivery said get yourself self one of the Craftsman stripped bolt remover kits. I have one of every size and they are flat out amazing. I would also apply heat and penetrating oil before using it as others have stated.

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