You might check with community colleges or tech schools that have an
auto tech program.  The one where I work usually teaches AC stuff in
the Summer.  You might get them to suck out the refrigerant, then you
take the van and do your work, then they evacuate and refill with the
refrigerant you provide or pay for.
Edward

At 05:15 PM 8/10/2010, Jeff Schwaia wrote:
>Ah yes, expanded gas as opposed to compressed.  My bad...
>
>-----Original Message-----
>From: Mike S [mailto:mikes@flatsurface.com]
>Sent: Tuesday, August 10, 2010 1:01 PM
>To: Jeff Schwaia
>Cc: vanagon@GERRY.VANAGON.COM
>Subject: Re: Replacing pressure A/C Pressure switch w/o losing Freon
>
>At 03:28 PM 8/10/2010, Jeff Schwaia wrote...
> >"270 liters of oily freon gas"...  You must have the optional
> >super-duper,
> >heavy duty A/C system!  ;-)
>
>R-134a weighs ~4.25 kg/1000 liters at atmospheric pressure and room
>temperature, so 270 liters is about 1.15 kg of freon. VW says the
>Vanagon holds 1.35 kg of R134a, so really, he must have the
>slightly-shrunken, light duty system.