Date:         Thu, 19 Jun 2008 12:54:30 -0400
Reply-To:     Roger Sisler <rogersisler2000@YAHOO.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Roger Sisler <rogersisler2000@YAHOO.COM>
Subject:      Re: AC High Side - line leak - rubber hose

Keith, new compressors have a shelf life of 18 months and then they may
start to leak from the shaft seal.You may need to charge in a can each
spring. If you are switching over to 134a, it is best to get a matching
expansion valve for 134a. Not hard to do as valves specifically for R12
don't exist anymore-except for NOS parts(and you don't want one of these). A
place called Vintage Air, in Texas, may have these R12 valves.

SIDE TRACKED A BIT HERE-- The R-12  valves failed in R12 Vanagons of
1983.5-1985 vintage because a disk that pressed upon the actuation needle
slipped out of place and jammed the system shut. This was a VERY  common
period  valve that was used in many different vehicles and after market
kits. Cars such as AMC, Ford and Lincoln are only a few. It was made by the
Singer sewing machine company(Do they exist anymore?).  The installation of
the Vanagon expansion valve was unique in that it was mounted sideways. All
the rest were mounted conventionally, with the "head" up, and worked fine.
During a very cold winter the R-12 in the sensing bulb and metal parts
inside would contract beyond the parts tolerances and allow the actuating
dish to slip sideways a 1/4 inch off center, and jam. When spring came, that
was it. Some slipped and some didn't. I took apart about 5 or 6 of these and
they all had the same problem. I stopped tearing them apart.

Your system of 50 feet of hoses needs flushing out to change the old oil. 80
percent of this needs to be removed. Ester oil is compatable with most newer
refrigerants and is a good choice ( Is this related to ester-c and ester-e
vitamins? :>)). Most of the nasty old oil is in the evaporator and does not
want to come out, so you  must get all the oil from locations that are more
accessible to meet the 80 percent standard. You will need to disassemble
most of the hose connections. I use mineral spirits, a funnel,  and a
compressor to do this, myself. Pour it in, let it sit for a few minutes,
blow it back and forth, and then out-repeat.

That vacuum pump thingie will work, but it needs to be left on for a long
time. Lots of people leave a regular vacuum pump on overnight. I don't know
how long you will need to leave that pump you have on, but it uses a
compressor, so the compressor will need to run for along time.


ANOTHER SIDE TRACK--- 1/20TH of 1 drop can shut an A/C system down. It
happens this way: Moisture circulates with the refrigerant and oil. The
dessicant bag in the dryer is supposed to attract and lock-up this moisture,
but it can become overwhelmed or damaged. Free water will circulate in the
liquid state and collect at the expansion valve where the refrigerant is
forced, at high pressure, through a pin hole. The refrigerant temapture
drops to below freezing at this point, and the water it contains turns to
ice. The ice starts to collect at the opening of the expansion valve and
eventually blocks the opening completely. The system shuts down. Water also
combines with R-12 to cause serious corrosion and oil contamination. If this
R-12 and water mixture is burned, it creates a Phosgene gas that is
dangerous. This gas was used in WW-1. Be surgically clean and desert dry.

After flushing out and vacuuming the system, and you are ready to charge-in
the R-12, do a leak test. Let your vacuum pump stay connected, but turn it
off. Watch the gauge for about an hour to see if you loose vacuum. Maybe
longer than an hour. If you have a leak, tighten up on the connection a bit
and retest.

Change the valve cores with cores rated for a/c systems. You can get them at
an a/c supply shop. Don't use cores that are for your tires. Valve cores are
a major leak source. All the hoses and such are non metric. If you have an
electronic leak finder, charge in a few ounces of refrigerant and do some
checking before adding the enitre 48 ounces, or so.  A soapy solution for
leak testing is very good and available a the a/c supplier. So are answers
to questions. If you can remove the evaporator, do it. Teh box that contains
this needs work  most times. There are seals that Home Depot can provide and
keep the air flowing best. This way the evaporator can be dealt with best,
too, this way. Make sure your drain tubes are well attached.


Good luck