Interesting post....

http://www.benplace.com/head3/100_0007.jpg

It's an operation...you need a PH.D...he he he

Like someone said, propane torch, not to hot, just perfect...2 minutes per
bolt, but before, remove all rust with a ice-pick or a screwdriver and a
hammer... now, test a 12mm (with rust removed, the 13mm is now smaller) or
even a 11mm, most of the time the 12 is just perfect.... tap the 12 socket
just to see if it fit..now, heat that bolt surrounding... when hot, tap the
12mm in hard... remove the bolt.

Cheers.
http://www.benplace.com/vw2.htm