Hi,
What if I want to up grade to R134a?  How does one flush out the old
lubricant (since the lube for R-12 and R-134a is different and incompatible)?
 I recently pulled a radiator/condser assembly out of a Vanagon and was
surprised at how much lubricant was "up front."  I'm going to be interfacing
the Vanagon's A/C system to my new Subaru engine/R-134a compressor.  Kennedy
(who is a nice guy, I drove up to his shop to meet him last week) never
connected the two systems together as he couldn't find a local shop that
could make up the hoses needed.  He's up in the high desert where there is
just not the same available resources as there is in the Orange/Los Angeles
basin.  I'm just getting to this part of the project.  Also, in reading up on
A/C systems, Vintage Air, of Texas, says that the Hoses used for R-134a
systems has an extra barrier as the gas will permeate through hose used for
R-12.  The VW service bulletin on R-134a upgrade doesn't address this issue,
is that because the cost would be prohibitive?  Or is this it a non-issue
with the Aero-quip hoses that were used on the Vanagons?  If the gas does
seep through the hoses, how often should one expect to have to check/add gas?
 Has anyone worked through any of these issues?  I've read many times of
Ken's recommendation of using Freeze 12 and if I was going to use a R-12
compressor I would explore that route.  Since, I have a R-134a compressor I
would rather stick with the R134a. Thoughts anyone?

Cheers,
Kevin Dawson
87" Wolfie 1/2 Camper