At 02:36 AM 06/16/2002 -0700, you wrote:
>With to the introduction
>of R134, AC hoses became known as "barrier
>hose" because the molecule of 134 is smaller than
>R12 and would slowly pass through the R12 type hoses.
>That said, it doesn't NECESSARILY mean they have to be
>replaced. Some people, just convert to 134 with the
>WalMart (or whatever) kit and plan on adding a can of
>134 every 6 months or so. At less than 4 bucks a can
>this is pretty cost effective.
When I was considering converting my '64 Merc to R134 I did quite a bit of
research. The most interesting bit of info relating to hoses and seals came
from the EPA's website. It seems that initially, when the EPA began
managing the migration away from Freon they recommended replacement of
hoses and seals that were previously in use on R12 systems. Now that
they've had enough years of field studies they've decided that the best
plan is to REUSE hoses and seals if possible. Apparently these items become
saturated with residue from R12 and it's lubricants and help increase a
hose or seal's resistance to leakage.
Unfortunately, when the EPA initially introduced their technical
information regarding retrofitting they mass-mailed every A/C shop in the
country with pamphlets and letters suggesting "replacement" rather than
"reuse". Of course the mechanics were happy to oblige since it means more
work and more profit for the shop. Now that the EPA has reversed their
position they have not taken the same measures to notify shops of the
change, and few shops have become aware on their own, so most mechanics
will still replace hoses and seals when doing a retrofit.
For a bit more detailed info on this topic you can visit the EPA page at:
http://www.epa.gov/Ozone/title6/609/technicians/retrguid.html
Best,
DD
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