exhaust manifold bolt is rounded off

Weld a couple nuts on it if it doesn't work the first time, put the plug back in first and you should be fine the heat cycle usually breaks everything free.

 

OP, are you able to remove the other bolts in the manifold along with the pipe flange nuts?
I have used every one of the above suggestions at one time or the other
depending on where I was and what equipement and tools I had available.
First I would try and hit the head of the bolt (using a cross pin from a rear end) to flatten it out and also knock the rust loose. Using a 6-point socket first try to tighten , then loosen the bolt.
Taking a manifold off in a junkyard once I had one manioold bolt that would not come out, I took all the other bolts out and used the manifold to work the bolt back and forth until it broke loose from the rust in the manifold, it was not rusted in the head. soaking it may help but the bolt is very long.
Third, it is not very easy to get to one of the center bolts to cut it or even weld a nut on the outside. It may be easier to drill it and knock the head off with a chisel. Then use *Nebraska pliers to get the "stud" out of the head.

* Nebraska pliers - Vice-Grips, made in Dewitt, NE

 

they would probably not work here , but Vise-Grips actually makes them specifically for rounded off bolts/nuts. i have a couple and they work great

i'm with the group that thinks that maybe you were using a 12 point socket , try a 6 point

 

I used a 14 mm 6 point socket. Put a breaker bar on the ratchet handle. Broke the socket. It cracked in half. Too much leverage. I also used PB Blaster penetrating catalyst. I am going to drill the bolt head off, remove the exhaust manifold, position the head on the work bench so penetrating oil can run down the threads, tap on the bolt a few times, heat it, then work the bolt stud back and forth with a craftsman stud remover if Sears carries it. Maybe NAPA has a stud remover. Thanks for all the suggestions.

 

There you go. If you wanna be pro though you gotta go to the grocery store and get paraffin wax in the canning section. Heat the stud right where it goes in the head and then jam the wax on it. Yah wax goes everywhere but when you back the stud out with your fingers and there is a drop of wax on the bottom of it youll never bother with anything else.

Oh and torches arnt supposed to be able the cut cast iron, so save your drill bits and time and just blast that thing off.

 

This is getting exciting! Not for you I guess..

 

from my experience ,cut head off bolt ,remove manifold ,soak stud into head with weasel piss, rap head of stud a few times, re soak with pf,then try again. ...If stud snaps off.... use center punch, make sure you are in CENTER of stud, drill out stud using small drill bits graduating in sizes up.Note:use plenty of cutting oil, then when almost to thread size chase hole with proper size tap.....easy, I,ve done in many times.

 

I'm gonna tuck this idea away in my noggin for another day. Great idea!

 

^^^^Tommy I was tempted to use Budd's idea. I was afraid the bolt would snap flush with the head. I ended up getting the exhaust manifold off by starting with a 3/32" drill bit and working up to a 7/16". Which is 1/16" larger than the diameter of the bolt shaft,. just in case the pilot hole was off a smidgen. The bolt head was stuck to two thin washers that were stuck to the exhaust manifold, Got out the Dremel tool with a fiber cutoff wheel , cut the bolt head off. The washers wouldn't come off. Used a sharp 1" chisel and whacked the washers off. Then, the exhaust manifold came off with ease. I did nick the exhaust manifold at 7 o'clock by the bolt hole. It is a shallow nick that shouldn't present a problem. Next step is to put the head on the work bench and melt paraffin down the bolt shaft to the last thread. Never heard of the wax technique mentioned, but I will give it a try. Thanks again for all the suggestions.

 

Heat is the key element. I usually get the bolt red hot then allow bolt to cool down before turning it out ,, paraffin wax or penetrating oil are secondary but required. I have never used the wax but i'll try it next time.
good luck

 

Let us know how the wax works, never tried it.

 

Yes inquiring minds want to know, wax no wax off

 

beeswax works awsome because it wicks and it doesn't matter what position the threads are in.

 

Always Tighten before you loosen. Just enough to feel it move. Same goes for bleeder screws. Don't believe me try it. Works 90% on rusted exhaust bolts and bleeder screws.

 

Thanks Bob! I did exactly as you suggested. Used an old dime store candle for the wax, heated the base of the exhaust manifold bolt and the head area around it, applied wax to it. It wicked and went down the threads. Let it cool, clamped on some vice grips, and with very little effort the bolt came out.