12a Rebuild: intake stud with frozen nut
 

Rebuilding the 12a and just discovered when when removing the intake manifold one of the studs under the coolant passage came out with the nut frozen at the end.

With the nut at the end of the stud, and not turning on further or off, it will not tighten down on the intake manifold.

Suggestions welcomed.

I'll check the auto parts store in the morning just in case I can replace the stud and nut.

If you can find two nuts that will fit, screw them onto the end opposite the stuck nut, jam them against each other, they will lock themselves to the stud allowing you to take the stuck nut off. Then chase the threads with a die so the nut will turn as it should.

It was very late last night.
This morning I realized I have two non-usable rotor housing, each with a good stud.

I should be able to pull one of them out.

Is there anything about putting the stud back in I should know?
Lock-tite or just in till its tight? That sort of thing.

Lock-tite sounds like a good idea to me.

Other than securing the intake manifold, its other purpose is to ease up on the installation. Other than that, a bolt works fine instead of stud.

or you can put a washer on your frozen stud and just put it back. think of it as a bolt

Thanks everyone.

I thought about the frozen nut+stud as a bolt, but more than one washer would be need to take up the slack, but if I could not rehab what I had that was the fall-back plan.

I double-nutted a stud from an old housing.
Then did the same to the frozen nut and finally got it off. The end of the "bad" stud became smashed somehow (??).

I used the housing side of the bad stud to clean out the two Mazda nuts.

All is well again and back to reassembling the engine.

Nice post, I learned more in a two minute read than I have all day.

Thanks Tim.

You tried vice grips on the smooth spot and a wrench on the nut?

Yes. That was the first thing I tried.
When the nut did come off, so did a small "cap" of the bolt. It was as if the end of the bolt was smashed. Something I did somehow.