Broken Exhaust Manifold Stud

[IanC]

Hi,
Can anyone offer some advice of removal of a broken exhaust manifold stud? It is the one nearest the bulkhead and has about 3/4' still remaining outside of the block.

Thanks in advance,
Ian

[kennatt]

if you have a mig welder weld a nut onto it and after cooling it should come out the heat from the welding frees it up,otherwise you need to be carefull using a pipe wrench get it heated up first.

[chickenjohn]

If the welded on nut doesn't work.....

If you can, heat the stud then use a stud extractor.

[bmcecosse]

Disconnect the alternator before doing ANY electric welding on the car.
Remove manifold and use a small stillson (= pipe wrench mentioned above^^^) wrench on it. If there is no room - you may need to take the head off. How did it snap ? There are brass nuts on these studs for a v good reason!!!

[MarkyB]

Don't be tempted to use an Easyout, especially a cheap Chinese copy.
If, or rather when, it breaks you have a much worse problem as the steel they are made from is rather drill proof.

If nothing else will shift it file across the end till you have a nice flat surface then centre pop it with a centre punch.
Then drill it nice and straight starting with a small drill progressing to larger sizes until there is little more than the thread left.
This should be easy to remove.

You can get left handed drills for this job which I hear good reports on.

[IanC]

Thanks guys.

I was reluctant to try clamping a wrench/mole grips onto what is left of the stud as I had visions of the problem getting worse before getting better!

I will give the welding a nut to what is left option a try first. Everything is now off the engine (which is still in the car) so no worries on the alternator front (but thank you for the warning).

This occured as I was removing the manifolds from the block ready to remove the engine. I soaked all the studs with wd40 over 3 days as I half expected this problem to arise! Then started to remove the nuts from the front of the block - I was suprised at how easy these came out. Then with new found confidence I moved onto the stud nearest the bulkhead. This one was dirtier than the rest and still caked in road grime / oil etc. When I applied the spanner and used the same force I had used on the previous nuts it sheared straight off.

I reckon that if I had cleaned and resoaked the stud it may have freed off like the others - Hindsight!!!

Anyway, thanks for the advice.
Ian

[Peetee]

WD is not the best for removing siezed fittings. Plusgas is leagues ahead in my experience.

[Kevin]

Hi Ian as Petee has said WD40 is not a proper penetrating oil even though it does many things, get some plus gas as mentioned and use some before going any further.

[bmcecosse]

As I suggested earlier - it should be brass nuts on there - precisely so they DON'T seize on the studs.

[MarkyB]

Relax, nobody suggested this wasn't true.

[kennatt]

you obviously have a mig,just fit a slightly larger nut over the stud and make sure you get plenty of weld into it leave to cool,it'll just twist off if you try it still hot,it will come out done it loads of times as long as you get a good weld it will work,make sure you don't get any weld splatter onto the faces of the engine,use something to cover the faces up,or anti splatter spray if you have some good luck

[IanC]

Thanks guys,

All good stuff - I will give the plus gas a try before trying anything else.

There was still a brass nut on the stud but I think what caused this was that having got the others off without any effort I didn't take the time to wire brush off the thread on the studd. There was a lot of crud around the stud and I guess this might have created a weak point - with corrosion. When I applied the same amount of pressure as the previous nuts off it came.

Thanks again for all the help and advice.
Ian

[bmcecosse]

Oh dear...

[Innovator]

It should be easy as you have a lot stuck out of the head. It is more of a challange when it breaks off flush.

Heat will help a lot and I am sure that is why the "MIG weld a nut on" works so well because the stud is getting hot.

I would try a stud extractor ( http://www.amazon.co.uk/Draper-14156-St ... B0001K9Q1S ) and give it a gentle tweak and see if it moves. If it doesnt then I would get some heat on it and then it will move.