A big question is who installed that pulley without properly tourqing it?
That is the only reason for it to fail. I would try a new key and a Loctite
retaining compound the glue it to the shaft and proper torque. Note that
there is an O-ring on the crank that fits into that bottom space on the
pulley to keep oil from working out through the  pulley bore. Make sure it
is there and correct one. I have seen the wrong O-ring keep the pulley from
properly seating on the crank causing it to loosen.

Dennis

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
Paul
Sent: Sunday, September 11, 2011 1:21 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Mutilated woodruff key at crankshaft

My girlfriend has been driving my vanagon pretty much daily. Recently she
said that she thought something wasn't right back in the engine compartment.
Well she was right, the bolt that's supposed to hold the pulley in place had
worked itself part of the way out. Upon further investigation I discovered
that the woodruff key was not in the slot, or what's left of it. It was kind
of in there on it's side and the slot is no longer a slot it's bigger than
it should be. One side is square but the other side is not good. I don't
have the time or $$ to pull the engine out to replace the crank so I'm
trying to fix it the best I can and hope it will hold up for awhile. Has
anyone had this problem and if so what did you do? I've considered trying to
drill a hole through the pulley and into the crankshaft, tap it and run a
allen bolt/screw in to keep the pulley in place. Maybe make the existing
slot larger and make a bigger key.
Any help or insight would be greatly appreciated as I need to get the rig
back on the road.
TIA,
Paul
85 WWW, 1.9L