Taking off the headers (stainless) this weekend and one bolt refused to come out.

Somebody else has obviously had the same problem and the double helix head has rounded off.

The bolt is difficult to access even with the engine out and I cannot get a grinder on it.

Any suggestions please?

Martin.

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Can't reply to this in any other way than to edit the article.

1. Weld another bolt to the top of the existing bolt.
2. Get in there with a Dremel grinding disc and cut a screwdriver slot.
Steve


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Drill the bolt head off. Then once header off, there's a bit of stud left - enough to get off with mole grips or external stud extractor (DON'T EVER use the tapered internal ones - terminally poo!), or as above, weld a nut onto the stud (never got the nut method to work myself though). Get a good amount of heat (red hot) into the stud if its a bit stuck and should come out fairly easily.
If still fails, grind stud so surface is flat, and VERY carefully drill down the centre of it, going up 1 drill size at a time. Eventually, you'll end up with a little spiral of thread which you can pull out, or if all else fails, helicoil it.

Done all the above loads of times - not as much of a nightmare as it sounds as long as you're careful.
Matt

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I agree with matts approach. +1 dont use an internal stud extractor!
This type of extractor would be better than mole grips:
http://www.kctools.com.au/images/TOOLS/TOOL%20JPEG...
Eliot.

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Shame on me for using the m word.
Matt

The UK available version of this seems to be the Draper 14156 1/2-Inch (6-19 mm) Square Drive Heavy-Duty Stud Extractor