Hi Lund,
I converted my system to R134a. I also replaced all the o-ring seals
with those new green-colored R134a compatible ones, because
my system was leaking.
VW does make a kit that is about $26, but it is not worth buying,
since it only contains a few connectors and a pretty R134a sticker.
It does have some useful instructions in it, and the quantity of R134a
required in your system.
You can read the VW instructions that came with the kit in the archives.
I posted them and also posted the work I did to repair my a/c system and
conversion.
You can read my posts by searching author under  harald.nancy
for dates 5/8/98 and 5/13/98 under title Re: a/c rebuild and retrofitted to
R134a.

One thing to mention:  VW  recommends removing the old
oil from the compressor, before pouring in the new R134a compatible oil.
I guess that you can either use a vacuum pump, like for bleeding brakes,
or take out the compressor and turn it upside down.
VW also recommends replacing the drier.

My archived posts also includes information on a good low-cost supplier.
I've been using my system since May, and it still works flawlessly.

Harald
'90 westy

----------
> From: Lund <wlund@CCIS.COM>
> To: Vanagon@VANAGON.COM
> Subject: A/C, R-12 to R134 Conversion
> Date: Saturday, July 04, 1998 10:38 PM
>
> To all:
> I would appreciate people's advise about converting to R-134 on 88
Vanagon.
> What is involved?  Does VW make a change-over kit?  My present system
went
> "flat" shortly after I bought it and I want to make sure I do the job
right.
>
> Thanks,
>
> Bill Lund