I've observed this problem with two brand new expansion tanks...  I first
thought I'd somehow damaged the threads while trying to stop the cap from
leaking but when I had the same issue with another new tank I decided the
tanks were both defective.  Another new tank from a different supplier (Van
Caf�) confirmed that the first two tanks were somehow defective.  

The first clue I should have noticed and given more weight was that the over
flow nipple was pointing straight back (when tightened) instead of sideways
towards the overflow tank (behind the license plate).  The new tank has the
pressure cap's nipple pointing in the right direction has been working
perfectly for 4 months.  

According to the Van Caf�, all of the available replacement expansion tanks
are "aftermarket" as OEM tanks are not available.  Perhaps VW's Vintage
Parts division will take this part on in the future?

Rocky Mountain Westy does make very high quality Vanagon parts...  I'm going
to try one of their replacement tanks in the 88 Wolfsburg Weekender that
I'll be working on next month.  

Andrew

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
WILLIAM WITZ
Sent: Friday, September 27, 2013 12:06 AM
To: vanagon@GERRY.VANAGON.COM
Subject: Expansion Tank Defect

The threads on the tank will not pull down the cap it feels like� they are
rolling when tighten them I got the same result with another new cap when I
tried to secure it. I know that it seals on the top gasket but the
mechanical action is not allowing it to pull it down without the Teflon
tape.
Bill Witz 84 Westy