I changed my '85's AC to R134-A almost 3 years ago and it's still
holding its charge.  I haven't added any.  I changed O-rings and the
receiver dryer but kept the original hoses.

I think they're not leaking because they had become "Seasoned" ... much
like a cast iron skillet becomes seasoned.

Mike C.

Roger Sisler wrote:
> Another consideration- 134a will need new barrier hoses to prevent leaks.
> If you dont mind a leaky compressor and wrong hoses , you will be ok.Just
> recharge every year till the compressor cant take the pressures anymore. 50
> feet of barrier hoses , using your old fittings will cost about
> $350.Commparison of the two molicules is that the R_12 molecul(sp-again!)
> is like a beach ball , and a 134a molicule is like a golf ball.It will
> migrate through the rubber.Being enviornmentaly correct with vanagon a/c is
> difficult any way you go, unless money is of no concern.It may actually be
> much cheaper to go r-12 is many cases.
>