You need a thin wall 17mm socket. Now please don't tell me you loosened and removed all the nuts except for an end corner!  Head especially on Waterboxers have to be de-torqued just the same as they have to be torqued down. If they were somewhat loose than either they were not properly installed or the engine was over heated to the point the studs stretched and they are now garbage. The head (and even the case) may also warped and twisted. This will show up as internal leaks with combustion gasses getting into the coolant system. 

Dennis

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of J Stewart
Sent: Sunday, February 9, 2014 5:59 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Yet Another Head Pullin' Question.

OK, just the other night I pulled a head off my "spare " 1.9 motor, and I can't for the life of me remember how I got the lower rearmost head nut off. Now the scary part was, on the spare the head nuts were not really tight, the ones on my 1.9 thats IN the van are. They are all out except that one, I cannot get a socket on it. TIA, Jeff

Jeff Stewart