A VW technical bulletin on the 134a retrofit:

http://www.gti16v.com/tb879503.htm

Be aware that in some editions of the Bentley the labels for the high and
low side are reversed; if you try to charge into the high side you could get
some undesired excitement.

Cya,
Robert

On 5/6/08, Jim Felder <jim.felder@gmail.com> wrote:
>
> At one time someone posted a link that described the connection and use of
> a
> manifold gauge. Could anyone point me to that?
> Thanks,
>
> Jim
>
>
> On Tue, May 6, 2008 at 2:02 PM, Mike Collum <collum@verizon.net> wrote:
>
> > Well, FWIW, I converted my '85 Westy to R134-A in Sept. of '02.
> >
> > What I did was, I replaced the receiver/dryer, removed the compressor
> > and drained the old oil out and flushed it, flushed the system, replaced
> > only the O-rings that were disturbed, put Ester oil in the compressor
> > and put it back on, drew a vacuum in the system and let it sit for about
> > 3 hours then added oil and refrigerant.  I didn't replace the expansion
> > valve.
> >
> > I've had to add a little refrigerant each spring but the charge
> > certainly doesn't leak right out.  My guess is that the old mineral oil
> > coated the old style hoses over the years which made them less prone to
> > leakage with the R134-A.
> >
> > Mike
> >
>