Get a new pair of 'quality' vice-grips.  I bet yours are old/ worn/ smooth
jaws/ cheap HF ones.  Use the ones that have a curved jaw with sharp teeth.
Works every time.
  If they're slipping, they're the problem, not the bolt.  I just removed my
axles and had to use vice-grips on the outside of half of them!  The cheap,
worn ones slipped no matter how hard I clamped them!  The good ones bit in
so hard that they left tooth marks.
Ymmv,
Mike B.

--------------------------------------------------
From: "Scott Daniel - Turbovans" <scottdaniel@TURBOVANS.COM>
Sent: Monday, August 09, 2010 6:54 PM
To: <vanagon@GERRY.VANAGON.COM>
Subject:      Re: Well so far it's beat me. >:-(

> hi ,
> it's not 'taping with a hammer' on top of stuck cv joint screw..
> it's very sharp severe whacks, not 'thud' ..
> but sharp whack.
> with a short drift and good ball been hammer,
> give it like 20 of those.
> 10 might be enough ....of .really sharp hard whacks if using the chisel
> method below.
> for the screw whacking I  use an old king pin for a drift..
> it's extra hard steel, really transfers the force.
>
> then with the chisel you're going to unscrew it in a circle with the cold
> chisel.
> dig a hard notch in the top outer edge of the screw, aimed in the
> unscrewing
> direction.
>
> somethings it's hit the chisel 40 times..
> or much fewer if you're lucky ..and it'll unscrew finally.
> then remove it with the vice grips.
>
> there's anohter pre-chisel trick, and that's to tighten the screw some
> first, or if it won't unscrew, tighten it some if it will, that helps them
> unscrew nicely sometimes.
>
> the upgrade 12 point screws are better..
> need a special tool, but they are harder metal.
> I've seen just one of those stripped out in hundreds of vanagons and cv
> joints and screws...
> and umpteen stripped out 6mm allen ones.
>
> scott
> www.turbovans.com
> ----- Original Message -----
> From: "Courtney Hook" <courtneyhook@SHAW.CA>
> To: <vanagon@GERRY.VANAGON.COM>
> Sent: Monday, August 09, 2010 3:27 PM
> Subject: Well so far it's beat me. >:-(
>
>
> Alright, I've gotten every CV joint allen head out except for one on the
> stub end. The AH PO obviously was a wanker, as there is NO way this thing
> wants to come out. He must have had the Incredible Hulk torque it up for
> him. Did I mention that it already looked like he re-used a bolt that was
> somewhat ovaled instead of 6 sided!!Things I've tried so far after WD-40
> over the last few days, and tapping it with a hammer:
>
> 1) Quality Crafstman allen head socket and ratchet. No way, just spun out.
> 2) Vice Grips on outside - just spun around the bolt even though I reefed
> them on there as hard as I could, and checked I had clearance to spin the
> grips. No way.
> 3) Took a cold chisel and ridged the outside circumference to get the vice
> grips to bite better instead of spinning. No way, still spun. :-(
> 4) Threw a temper tantrum and spoke in tongues I learned in the Army. Wife
> not impressed. Me either.
>
> So what's number 5?? Get out my mig, and weld an allen wrench piece into
> the
> hole and use it as an "extension" Little worried about the grease, oil,
> gas,
> electronics about this one.
> Thanks,
> Courtney (Eyeing some Bud Limes right about now so I don't start speaking
> in
> tongues again)
>
> ++++++++++++++++++++++++++++++++++++++++++++++++++
> Always be yourself, because the people that matter don't mind,
> and the ones who mind, don't matter.