It's possible that the contact(s) in the bottom of the bulb socket is so corroded or bent they don't have enough spring to make good contact on the bulb.  Try prying it up a bit, and if it breaks off you need a new tail light assembly!

Stuart
'85 Westy

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of John Lauterbach
Sent: Saturday, October 26, 2013 5:58 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Intermittent right rear stoplight '84 Vanagon

The right rear stoplight on my '84 is being problematic.  I have tried
several different bulbs, bulb grease, cleaning contacts, etc.   The
taillight and directional signal light work correctly and consistently.
I can have the stoplight working after I put everything back together and screw the light assembly back into the van.  Within days it will stop working, but as soon as I take things apart, it will start working again.

What is best solution to this problem?

John