Robert Dalton wrote:
>
> When Larry A converted his 91, I wonder if he had to
> change hoses.  In 93 VW was using barrier hoses,
> because 93 EVs used r134.  I just wodered if you could
> get away without doing this PITA hose change?  On my
> 80 Westy, I shudder to think of what would happen if I
> tried to take off the old hoses.  Something expensive,
> or impossible to replace would undoubtedly break.
>
> Rob
>
The only things I changed were the receiver-drier and the O-rings there
and at the compressor, which I disconnected to empty out as much of the
old oil as I could.  I considered changing the expansion valve as some
people recommend, but when I realized how much trouble it was to drop
the evaporator, etc., I decided to try skipping it.
  I am aware of the barrier hose issue, and I will not be suprised if I
have to recharge occasionally, but one or two cans of R134a per year is
a lot less trouble and expense than changing the hoses.  When I checked
the performance after about 2 months, it seemed to still be fine; air
temperature leaving the evaporator got down to about 48 F.  My overhead
tunnel fell down some time before I fixed the AC and I have just left it
off.  The air seems to get up to the front just fine, and we don't bang
our heads anymore.
  I believe that ester oil is the way to go. From what I have read, the
original mineral oil is incompatible with R134a, but if some remains in
the system, it will dissolve in the ester oil and not be a problem.  PAG
oil is used in factory R134a systems, but requires complete flushing of
the system in the case of a conversion.  It is also said to be rather
toxic.

Larry A.