>My '69 bus had hex socket-head bolts holding its CVs on. When I replaced
>one, couldn't get them loose, so clamped my vice grips on the end of the
>cheapo allen wrench I was using. SNAP.

Ack. Put the vise-grips on the bolt head, people, not the tool. Then try to
apply exactly the same torque to both the vise-grips and the tool
simultaneously. They'll come right out. If I'm not the one who put the bolt
in, I now do this as a matter of course, otherwise 50/50 the thing is gonna
strip even with the right tool.