sheared manifold stud - steve_rt
hoping someone can help! am working on a polo to bring up to scratch and sell on. The manifold is cracked and am therefore changing it - however, going to undo one of the manifold-head nuts today, and by just touching (and im not exaggerating here!) the nut, the stud sheared, obviously already weakened and just waiting to be touched. anyway, some of the stud has come away with the nut.

how do i go from here in trying to put a new stud in? ive used bolt extractors before but am i right in thinking you cant extract the stud in the same way, as its not meant to come out?! if so how is it remedied? is it a head-out job?


sheared manifold stud - Sooty Tailpipes
Well, is there room to double-nut it and take it out with a socket?
If stud extractor don't work, you might have to take the head somewhere for them to take it out with spark erosion.

Good luck!
sheared manifold stud - Hugo {P}

Try this - Plenty of useful suggestions from a few weeks ago.

Best of luck

sheared manifold stud - steve_rt
cheers for the link hugo, given me lots of things to try. not such a good welder (in fact ive never even picked one up) so wont try that, I didnt realise that the studs themselves actually screw out though! so as i understand it, leaving penetrating oil in there for a few days and then attacking it with a pair of mole grips on a flattened part of the stud is the best option.

i remember something about threading two nuts onto the stud and somehow forcing it off like this? would someone be kind enough to explain how this works?

lastly, the stud isnt reverse threaded is it? ie it will come out if you turn it anti-clockwise?

thanks for all your help,

sheared manifold stud - Cliff Pope
Threading two nuts on one stud can work, but IMO only if the stud is not too tight, and would probably have come out easily with mole grips anyway. I find it better used as a way of putting in a new stud, without risk of damaging the thread with grips or something.
What you do is put the two nuts on, and tighten them together. You need enough thread available for both nuts. Then to undo, turn the lower nut. To screw in, turn the upper one.
In theory the turned nut jambs against the other, so the stud turns not the locked nuts. I find if the stud is really tight that all that happens is that the two nuts rip the thread or else break the stud inbetween them.
As I say, best used as a way of inserting a nice new lubricated stud.
My tip for removing anything stuck is once you have got any movement, apply more penetrating oil and leave it, then RETIGHTEN, then ease it out a bit more. Repeat a bit at a time. If it has sheared once it is liable to do it again if you apply too much force.
sheared manifold stud - Sooty Tailpipes
You put two nuts on, then tighten them against each other in opposite directions as hard as you can and then they shouldn't undo as you use them to unscrew the stud.

Also, you could try one nut JB welded onto the stud.

You can get it from Wilkos, DIY and Automotive shops.
I have used it for all kinds of things and reckon it would work if left to harden for a couple of days, and the threads free of oil.
sheared manifold stud - pastyman
In answer to Dizzys answer a few weeks ago, plus gas is extremely good and it is also available in a aerosol can form.
Apart from all the excellent replies, once the penetrating fluid has done its work, if you can, give the stud a smart tap with a hammer straight on the end of it, this sometimes helps to break a corrosion bond.

sheared manifold stud - Hugo {P}

If you can get two nuts on it DO NOT attack it with molegrips. This will make it much more difficult to achieve a result.

I would soak the base with penetrating oil and then put the two nuts on turning them against each other. If you can get the hexagons to line up all the better, but if you can't dont worry.

Perhaps judicious tapping as suggested by Pastyman plus a rocking action with a spanner may work. Try to 'feel' how the stud is behaving.

Good luck

sheared manifold stud - steve_rt
thanks for all your help and advice - i have devoted saturday to changing the manifold, so this stud better not be too much trouble!

i really dont want to ruin any chances of gettign this out though - in your opinions are they often successfully removed, easily?

i plan to try in the order as follows:

1. soak in penetrating oil for 24 hours, re-apply shortly before attempting removal.
2. hit with hammer to dislodge it.
3. attempt removal with 2 nut trick. can i just confirm that i have understood this right? by locking the two nuts against each other you then use a spanner on the nut closest to the engine, turning anti-clokcwise. the fact that this nut cant mvoe as its locked with the second nut means that it will attempt to move the stud. am i getting this? sorry for my apparent stupidity!!!
4. if this doesnt work i will attempt to wrench it with mole-grips, perhaps filing down opposite sides to create an edge grip.
5. kick it! ;)

cheers everyone for your help, if anyone thinks im doing it wrong above let me know!

sheared manifold stud - Sooty Tailpipes
You are right with the two nut trick, you can put a socket over both (if you align the flats) if this is easier and they are tight enough against each other, you'll soon know if they start to turn that they aren't and can try tightening them more.

As for the Plug gas, I reckon its much better than the usual WD40 sprays, it is a much thinner and 'wetter' stuff.

Maybe also worth heating it again when you come to undo it?
sheared manifold stud - steve_rt
sprayed it today, smells worse than WD40 - my usual line of thought is the worse it smells the better it will work!

yeah i was thinking of applying heat aswell, just dont want to apply too much local heat and warp the head!

thanks for everyone's help.

sheared manifold stud - steve_rt
sorted it yesterday in ooh, about 2 mins - the stud simply turned when gripped with moles! but i used the two nut mothod to undo some other stuck studs and to put them in, brilliant method!

and the plus gas is my new best friend!
sheared manifold stud - Hugo {P}
Nice one Steve!

Thanks for getting bck to us with the results. It's nice to know that our wild guesses work! :)

Now we know how you did it, we are better prepared should any of us hit a similar problem.

Thanks again for the update and above all - WELL DONE!


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