I have seen the plug you refer to, Bulley.
Always wondered what it was for.  Once again the wisdom of the list
prevails...

-----Original Message-----
From: GMBulley@aol.com <GMBulley@aol.com>
To: pdooley@GTE.NET <pdooley@GTE.NET>; Vanagon@VANAGON.COM
<Vanagon@VANAGON.COM>
Date: Saturday, July 11, 1998 2:37 PM
Subject: Re: Need a/c hose for 87 Westy Gl

>In a message dated 98-07-11 14:01:05 EDT, pdooley@GTE.NET writes:
>
><< Wow, I guess I stand corrected on the pressure switch deal.  I just
figured
> any responsible auto manufacturer would put a high pressure switch on an
AC
> system.
> Sure, in production runs as high as VW this would be expensive, but not
> nearly as much as litigation an recalls.
> When did VW start using them?  My 77 scirocco had them, so does my 86.  I
> never bothered checking my van, haven't got to that point in the buildup
> yet. >>
>
>Sadly, I don't have one to look at (Westy with AC wannabee). Help me
>out...Doesn't the bottom of the receiver-filter-dryer have a one-shot, blow
>off-valve for high pressure??? I thought all them did. It is a little 10mm
>bolt, with a plug of alloy in the center that melts at a very certain
>temperature, acheivable only under sickening pressure.
>
>This plug keeps your AC system from completely fritzing when you don't
change
>the filter/dryer or run into any other high pressure situation (360-degree
>performance review, home loan appraisal, birth of septuplets, etc.) Don't
>Vanagons have these???
>
>gmbulley
>cary, nc