(I tried sending this before...nothing happened...might be useful for someone.  So am trying to send again.  Will NOT be offended if of no use for anyone.)  

I wanted to fix my 85 Vanagon A/C after doing the Subie 2.2 conversion.  Conversion came with a Subaru A/C compressor; my converter had to get a couple new lines made.  Re-filled system with R-12.  Excellent!....for about 2 months...doh.   So there is this local San Diego A/C shop who knows Vanagons; took it to him.  Using "sniffer" thing, discovered many leaks; most were O-rings, easily fixable and they did so.  However....there was still one small leak coming out of Evaporator (on an 85 Tintop it's a big monster contraption hanging down from ceiling behind front seats).  To fix that would be like $2000....and super brittle plastic housings.  By Federal Law, he could not add R-12 to a system that had been determined to have leaks.  So the decision was made....convert to R-134A.

All was good for about 9 months.  But, slowly weaker performance.  I asked my guy about that Stop-Leak product available for R-134A.  He said, Yes it might work, or help at least.  Here is the Big Thing though:  once you have that Stop-Leak stuff in your system, it opens a whole can of worms.  If you ever need your system evacuated, it will RUIN a shop's equipment.  So nobody will work on it, and you are on your own forevermore.

I considered all my options....and decided to try the Stop-Leak.  Worked very well, like magic.  Still a tiny leak from somewhere.  So now the situation is:  every year around June 1 or so, I hook up my gauge set, and add a can or so of R-134A to the appropriate High and Low Side pressures.  It generally lasts all summer and fall.  Over winter and spring, I never need A/C of course.  But then come June 1, I repeat the cycle.  

Not sure if the wisest approach and decision-making.....but so far so good.
Rich
San Diego