John, this is the best time to convert to another refrigerant.  I like the
Freeze-12 refrigerant but there are some places where this is hard to get or
shops won't use it (they are unfamiliar with it).  In that case I would
recommend going to R-134a as this is easy to get and all shops now do these
conversions.  My recommendation either way you go is to replace your
expansion valve (new ones are set up for R-134a pressures) and
reciever/dryer.  When the system is open for any length of time the dessicant
in the dryer gets swamped with water and the filter could be contaminated.  I
would also flush all of the lines and change to Ester oil at the same time.
This has been my best results for either R-134a or Freeze-12.  I have used
Freeze-12 as a drop in replacement in low R-12 systems and it works
excellent.  R-134a seems to work best when you do a full conversion.

The A/C in campers is good for the people in the rear seat.  The folks in the
front wind up with a frozen back of the neck and a hot forehead, but unless
you want to fabricate some extra ductwork, this is the best you can hope for
in any vintage westie.  Hope this helps.

Thanks,
Ken Wilford
John 3:16
www.vanagain.com
Phone: (856)-765-1583
Fax: (856)-327-2242

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