sheered off stud

[sdp]

I'm looking at getting a mini cooper cylinder head, I've seen one and he wants £55 for it but it's got a sheered off stud (it's one of the heater valve ones).

How hard would it be to repair? I know about stud extractors but I don't wanna fork out £50 on it if there's a chance I might make a mess of it..

[Jiff Lemon]

Never had much luck with Stud extractors. You options include:

1) as its a cast iron head, apply lots of WD40 or similar. Then apply LOTS of heat. If you've anything left of the original stud, grip with a GOOD pair of mole grips and gently work it to and fro, keeping the heat on.

2) if it's snapped flush with the head, you could try grinding a slot into it, then (with heat and WD40), using a screwdriver to wind it out.

3) Drill the damn thing out and helicoil it!

[IainB]

Or if your feeling very clever, drill out the centre and then tap the threads in on themselves..... not the easiet thing to do (as you need to ensure your in the centre when drilling) but does work quite well.
Failing that, heat, WD40, drill down the centre and use an eazi-out to unsrew the stud.

[sdp]

Cheers, i decided against buying the cylinder head in the end; he'd put it on ebay.