At the point you flow water through the system you can probably write it
off. Use an AC flush to really try to get it out. The vacuum pump will love
that water going through it. Even normal compressed air can be trouble. The
receiver dryer is a desiccant type filter and should be replaced most any
time the system is opened for other repairs. Especially if the system is
open for any length of time.  If the refrigerant was push backwards through
it the filter could be damaged and anything it trap was blown through the
system in reverse.

I would replace the expansion valve since you are holding it with an R-134
valve and the receiver dryer. Make sure the radiator fan is working. High
pressures are common on these as the fan really does not cool the condenser
sufficiently especially on the pre '86 models.

Dennis

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
Karl Wolz
Sent: Sunday, September 04, 2011 11:47 AM
To: vanagon@GERRY.VANAGON.COM
Subject: Another AC question

'85 Westy with 2.1L, using R-12

Only blowing around 80 degrees (better than 112, but not by much), mechanic
says 300lbs high side pressure and only about 10 lbs low side.  Says he
suspects a blockage "somewhere".  He drained the R12 and blew through the
condenser - says that's clear.

Due to my ingnorance of things AC, the hoses were initially hooked up
backwards at the compressor.  Mech says running the system in reverse may
have damaged the receiver/dryer, causing these symptoms.  Last night I
pulled out the expansion valve and am able to blow through it.  AC parts guy
says that means little, as it could be locked open or closed (this means
little or nothing to me [I feel like Rocket with this series of questions]).

I bought brass fittings last night with which to hook up a garden hose to
the system (sans compressor & receiver/dryer) to hopefully flow out any crud
hiding in the system, with the logic that any water inside will be boiled
off when a vacuum is pulled prior to recharging.  Anyone care to comment on
the wisdom of this procedure?

Hoping for cooler air,

Karl Wolz