Well, it's leaking from somewhere!  Those hoses shrink, stiffen, and develop micro pores as they age, and they are very long.  The higher the temps they are exposed to and the more ozone you have in your air the faster the breakdown.  Replace them as a first step, and recharge with the refrigerant of your choice.  You will likely be fine just doing this. 

They will have to be custom made of course, using your fittings.  Good luck!

Stuart

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of Dave Mcneely
Sent: Tuesday, January 21, 2014 1:25 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Air Conditioning help

My 1991 Volkswagen Vanagon GL Campmobile with factory air conditioning and a 2.1 liter engine (159k miles) loses refrigerant over the course of a summer.  It had it converted to R134a two springs ago.  It got all new fittings, the system was flushed, and new proper lubricant for R134 was added.  It cooled wonderfully well, but by summer's end it was not doing so, despite two shops claiming not  to be able to determine that it was leaking.  They reported that with a "leak down test" over 24 hours, it held proper pressure.

So, next spring it needed recharging again, and again, "leak down test reveals no leak."  By summer's end, it was not cooling.  Recharging resulted in the thing cooling marvelously, air temperature from the plenum being around 48 F.  So, what do I do now?  I plan to use the camper this spring, summer, fall and will need air conditioning for some trips through the plains and Southwest.

Help!

David McNeely