O.K., so you are trying to unbolt something on your car, BUT the head
of the bolt breaks off (and unless you're one of the few who owns one
of the newer Mexican Bugs, your car will be at least 28 years old. I've
been there too). Of course, you may have to drill and tap if the
remainder of the bolt is flush with the surface, but if there's at
least 1/4 inch sticking out, you can grind the "sides" of the bolt flat
with a Dremel, then you can back it out with an adjustable wrench. This
trick may work with studs as well.

Joe

Your Moderator And Proud Owner Of A '72 Super Beetle