How NOT to repair a broken manifold stud

4SPEED427 · A Poncho Legend!

How NOT to repair a broken manifold stud

64 Canso · Veteran Member

What I do:

If some of the stud is sticking out I usually weld something on, heat red hot and try that.

If that breaks off, I drill for suitable easy out, tap in, heat red hot and try that.
If that doesn't work I drill out to the major diameter of the thread(3/8 bolt=3/8 drill), perfectly centered of course. Then I take a pick and pick out any threads that I can, then I retap.

Good luck, Floyd.

4SPEED427 · A Poncho Legend!

The stupid thing is, after doing this I realized my mistake. I drove the 6 miles to the dealership I work at, put the heat on to the manifolds and pulled the other 5 studs (2 manifolds) out in about 10 minutes flat. I was just trying to save the trip there and do it all at home. And that includes on stud that was already broken flush that I welded a nut to and turned it out.

Stupid, stupid, stupid...................

I have learned a very good lesson.

I think I will likely just get the broken piece brazed back on. It broke in such a way that a stud actually still threads in with the piece missing, so it should work ok. (Meaning the broken piece is less than half the circle of thread.)

Taylor55 · Poncho Master!

To remove broken manifold studs is not that hard to do providing there is at least 1/4 inch showing. Use a drift punch tapping the stud at the bottom where the remains are sticking above the manifold. 2 or 3 good shots and the studs will loosen by breaking the rust that was seizing them. I just did this on my Dad's 47 Plymouth where all four studs were broken that hold the intake and exhaust manifolds together. I had the four studs out in less than 10 minutes with no heat.

Al

4SPEED427 · A Poncho Legend!

It was me just trying to take a stupid shortcut. I knew perfectly well that they would come out easy with the proper tools and technique. I guess I still haven't perfected "perfect"!

59stratochiefwagon · Veteran Member

A 3/8" threaded hole should be drilled with a 5/16" bit. If I cannot get the bolt/ stud out by heating and or welding I will drill a pilot hole in the stud then drill it out in stages until I get close to the thread dia and then pick out the threads , Henry.

-- Edited by 59stratochiefwagon at 10:52, 2008-06-30

Ghost Post · Poncho Master!

Lots of good advice but keep in mind whenever removing seized bolts/studs, if possible it's always best to heat the metal that surrounds the bolt, not the bolt itelf..
The heat expands the metal so best to expand the metal away from the stud, not heat the bolt and expand it into the surrounding metal..

The heat can also weaken the bolt so another good reason not to heat it if possible..
If you can't heat the surrounding metal without heating the bolt at the same time, have some water handy so when all is aglow, dip a straw into the water and thumb the top to carry the water then apply a touch to the bolt only so it shrinks while the surrounding metal stays expanded..

On other old motors, especially Oldsies & Cadillacs, if one stud bolt broke I always used to torch the heads off the rest, remove the manifold then heat the head around the stud grabbing the protruding stud piece w/ Visegrips..

Another old timer trick worth a try sometimes is get the stud and surrounding area hot and melt candle wax into the threads...sounds dumb but the wax creeps in between the threads and works amazingly well!.

-- Edited by Ghost Post at 12:10, 2008-06-30

4SPEED427 · A Poncho Legend!

Learn something new every day. I never heard the wax trick before.