Looking for suggestions....

[84E24]

in getting an exhaust manifold stud out of an alum. head while it is still in the car.

I pulled the exhaust manifolds off my 35 year old coupe. All the studs were rusty and all but the lower middle one at the rear would not come out. All of the studs came out of the head. The nuts would not move. This only took about 3+ hours !!!

The studs have threads on both ends and a non-threaded area in the middle. The non-threaded area is bottomed out in the countersink in the head.

I have tried: double and triple nutted the stud... stripped the threads in the nuts and on the stud. Big axx vise grips... rounded the stud. Sprayed alot PB Blaster. Just won't go up hill. Heated the head and tried the vise grips... Have a 8mm stud remover... rounded the stud so the remover will not grip.

Any other ideas besides the obvious ( pulling the head )

Thanks,

 

[radosc]

You need serious heat and working it out. Clamp it and then while it is red spray some wd40 on it and move it slightly both sides. You will hear when it'll move, it takes some time though.

 

[Laldog]

Red hot heat

I agree with the previous post.

Soaking it with PB or Marvel Mystery oil helps, but I find that nothing is better than heat. Tappng it with a hammer and applying more lubricant while it is red hot has worked best for me.

 

[BarryG]

Funny thing about heat..
When you heat all the way around the stud you are swelling and putting pressure on the stud.
You might try to just put heat on half.that way you are relessing presure on the threads.
if when you get the head hot ...cool only the stud..
Hope this helps.

 

[x_atlas0]

Barry-

The thermal expansion coefficient of aluminum is several orders of magnitude greater than steel, which is what the studs are made of. The main point of heating the head and the stud is to shear the local bonds holding the stud in place, not to increase the size of the hole. Like you said, you'd ned to apply localized cooling for that. Howeer, if you did that, I'd be worried about cracking the head. Plus, you'd need something really, really cold, which is a bit more expensive than something really, really hot.

84E24-
Since you obviously don't plan on re-using the stud, you could try drilling some small holes through it, sticking some nails through it, and then clamping on them to get some additional leverage. Or, if you are getting desperate, weld something to the stud and break the sucker out with effectively a breaker bar. I've seen some people remove the main crank nut the same way.

 

[Bill Riblett]

If you have a MIG welder, try welding a blob on the end of the stud.
This will:
- heat the stud, maybe helping break the corrosion bond,
- concentrates the heat on just the stud,
- give you some more material to grab,
- the blob will be harder than the stud.

I've used this method to remove broken studs. Should work here.

 

[BarryG]

Bill thats a great way to do it...
I have mig a nut over the stud and that heats the stud up and my help.

X sorry in a bit old school

 

[saveacs]

agree with heating the stud very hot. this will put the heat into the aluminum threads. if you rapidly cool the stud, abovementioned bonds should break. Do it several times. Red hot stud, douse. Red hot stud, douse. Once the corrosion is broken, ( I think it's called dissimilar metal corrosion) reasonable force should be all that's needed to remove. Any more than that and you risk breaking the stud off. Reheat and douse if necessary!
GOOD LUCK!

 

[Henrik]

Hi!

Before you start heating or drilling (which could destroy the threads) out the stud, I recommend you to give the top of the stud a couple of knocks from a hammer, with much force. This will help to separate the steel threads from the aluminium threads (softer). If you are lucky you can remove the stud with a vise grip.