Featured Technical Broken Exhaust Flange Studs

What is the best way to extract these. I was going to soak them in blaster but then I thought about welding a nut on the stud so I want it to be clean. I broke all three off.

 

You can soak them with blaster or liquid wrench. Then try double nutting them. They will be stubborn and probably need a torch to heat up the flange.

 

Clean studs with wire wheel, I like putting the nut about halfway onto the stud so you make sure you are penetrating the stud and not just jumping to the bolt, Crank up the amps on the MIG, let the red disappear and remove it with an impact gun.

 

Get it red hot and then clamp on vice grips. Should come out easy as you have quite a bit there bite on.

 

Hardly ever managed to rescue siezed studs from a rusty cast iron manifold. Get the drill and taps on standby.

 

In the car I heat the flange to a dull red before spraying on the penetrating oil and then let cool. If I am in a patient mood, may repeat a few times before trying removing using the double nut deal on the stud. Drilling them out is an option, but the access in the car most times isn't great and it's easy to drill off center if you don't have a drill guide, so removing the manifold is usually quicker. If the manifold is removed from the car, and I am not in a hurry, I will soak the flange in white vinegar and let some of the rust dissolve and then try the heat and penetrating oil before the drilling deal. The best approach is up front just accept it's seldom a quick no stress deal. But slow any steady wins the race.

 

You've been doing something wrong , hot wrench most always works

 

when you put it back together use brass nuts

 

Second on the brass nuts, plus I also put antiseize on the new studs before I install them into the manifold.

 

Technical - USE CANDLE WAX TO LOOSEN RUSTED ON BOLTS | The H.A.M.B.

 

Id do the weld but move the nut as high up on the stud as possible so its heat cycle will penetrate into the manifold. And dont let them cool, as mentioned above, after cherry red has gone away, start wrenching them off. do 1 at a time also helps. The heat and the leverage is key.

 

25 other threads on "Broken Stud".
https://www.jalopyjournal.com/forum...en+stud&o=relevance&c[title_only]=1&c[node]=5
I'd guess there are at least that many again that have something different in the title.

 

I guess I do it different from the rest of you.
Clean the flange and use some penetrating oil just where the stud enters the flange.
Get your torch and heat just the stud until it's red hot all the way to the flange but do not heat the flange. (important that you do not heat the flange.)
Let the stud cool to the touch and use a double nut or vice grips to remove the stud.
The principal behind this is that the stud expands when heated red hot and then shrinks when it cools. This action breaks the rusty bond that has formed in the flange. Sheetmetal screws and body panel bolts usually come apart by hand with this method.

 

As Pocket Nick says above, try candle wax. Had bolt broken off flush on Model A exhaust manifold(where intake bolts to exhaust manifold) - built up stud enough with tig weld to get vice grips on and melted wax onto stud at manifold - may need to repeat heat and wax a couple times.
Have used heat (oxy-acetylene)and wax on double-nutted stud exposed to water jacket that wouldn’t budge - it worked.

 

One thing not mentioned yet is your trusty air cheisel/hammer. Use a smaller one and put it on low setting , use the bit that is concave and put it right on the stud. It takes some time, sometimes, but this sets up a vibration in the stud and can loosen the threads. I try this before the welding nuts and things. Like all the methods mentioned….works sometimes….sometimes not!





Bones

 

Lots of good ideas , don’t chuckle at the wax you will be amazed at the results . It works well . In the end I replace with stainless studs and brass nuts .

 

You have it easy with those - there's something to grab.
I have to disagree a bit with some of the answers.

Oxy-acetylene torch works great, but the casting is what's heated. It has to get bright red, when the studs screw out quite easily.
As the casting cools down to a dull red, it gets much harder to unscrew the stud.
This is what I learnt as an apprentice in a shipyard taking apart many many rusty cast iron valves, and it's worked great for me on automotive manifolds as well.

 

wow, lots of different ways... I used to work at a place in the 80's that did lots of exhaust systems on 10 yr old rusty Michigan cars. We just heated the flange of cast iron manifolds red hot, and stud would come right out. All the mechanics had "souvenirs" in their tool boxes of old rusted studs they removed to compare with others-"Who's is thinner??". Anyway looks to me like that stud will come right out and threads will be OK.

 

Even Mapp gas in a propane torch will get it plenty hot. I like giving it 2 to 3 heat-cool cycles.

 

Just as an aside, apparently real MAPP gas is no longer sold. The stuff in the yellow cylinders is now "MAP\\PRO", etc. which is not much better than propane.
Lots of talk about this on the Garage Journal etc.

 

My friend asked me to help him with an exhaust manifold for his small block chevy. He ended up breaking two off and left nothing to grab onto. He said he tried everything. This was about 15 years ago. We went to a good hardware store and got a good drill bit and drilled them out. We tapped them and installed new studs. It was a pain, but it worked.

 

Even if you don't have much of a stud left, Clean it with a wire brush, put a slightly larger size nut over the stub, and hit it with your welder, on pretty high heat. Be sure you are getting good weld on the stud, it will want to go just to the nut. I usually use an impact gun, right away, but you can use hand tools if you're fast enough. Never failed for me!

 

never ever ever drill them..

 

1946 caddy , is the first guy in this thread that understands how heat works ,,, his way works every time !!!

 

Weld a washer to the broken stud first, you can get to the stud easier, then weld a nut to the washer so you can get weld on three sides of the nut. The more heat you put into the stud, the better they come out.

 

Why not? I've done it several times over the years and it worked out fine.

 

Sometimes that is the only option, if they break off flush with the flange! I have drilled many, many bolts out of holes in my career! In my job , I encounter many rusted bolts and have used every trick mentioned here! Sometimes you just had to do what you have to do!


Bones

 

As a common denominator , Heat is your friend.
Vic

 

Heat being the way to go but…you could always drill the whole thing out and just use a regular nut and bolt to clamp it, if there’s room of coarse.

 

Help, actually makes a clamp to go over these bolts to “ repair” the broken bolt, so you do not have to drill them! I have never used one….but have seen them!





Bones