>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)?

Not entirely - a small amount of the old oil will always remain, and is
good, actually, as it serves as a barrier to prevent R-134A from passing
through the hose.

To flush out the old oil, get the tech to blow the system with nitrogen -
tons of oil will be expelled. I saw mine being done - wow!

Basically, do this for the conversion:

Before making a swap, Go to a AC mech, have him vaccuum-evacuate the old
system - if he blows it to the atmosphere, don't pay him - and report him to
the EPA.

Have him pressurize the system with nitrogen - then blow the old oil.

Then have him lightly pressurize the system with nitrogen.

Do your swap, release compressor fittings - wear heavy gloves!!!!!!!!.

Go back to shop, have him connect new compressor, install new O-rings, new
receiver-dryer.

Have him pressure and vaccuum test it with nitrogen, then draw a hard
vaccuum and pump in the r-134a and oil.

Have him test for leaks and proper pressures. (BTW: If he didn't know to do
all of the above steps, he doesn't know his job very well.) You're done.

If you want a system that is going to last and not leak, only a ac mech can
do the above.

Marshall Ruskin
84 Westy, converted by military ac mechs to r-134a last year.

> 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
>