Thread: V8 exhaust manifold studs

I would try heating the manifold and see if that loosens it otherwise may have to drill it out and retap the thread.

Try an industrial product called "Yield" made by Chemsearch of Alexandria, Sydney. Usually sold by engineer's suppliers like Blackwoods. Expensive but worth it. They call it rust dissolver. I call it miracle fluid. Otherwise get out the heating torch and heat the end of the manifold and the studs to a dull red and let air cool, then you should be able to get the vice grips on the stub and screw it out. Some Yield or WD40 applied when cool does help.

Use some WD40 or Brian's "Yield" on the threads. By all means heat too if you want.

Then get two nuts the correct size and screw them both onto the stud until they are completely threaded on.

Next, with one spanner hold the one nearest the end firm while you undo the other nut again with a second spanner (it should come up against the first). Tighten the nuts together as tightly as you dare without shearing the stud.

Then put your spanner onto the inner nut only and unscrew it.

If all has gone well the stud should unscrew with it. Once out you can use the two spanners to free the nuts again. Works 98% of the time and you can reuse nuts and studs (unless they have other damage of course).

Chris

bugger, bad luck mate.
I had heard of this happeing before so last time I removed the pipes I drowned them in wd40 every other night for about 10 days.
They came out a treat.
I have also seen replacement studs/bolts made from a copper or copper compound that can be used and apparently they don't get stuck.

Anyhow back to your problem

You can drill a partial hole of a smaller diameter than the bolt then screw in a tool ,(dont know the name) like a drill bit in reverse. I have only used one a couple of times and supercheap sell a cheap version of them.
Whatever it's called.