From: John De Armond
Newsgroups: rec.outdoors.rv-travel
Subject: Air Conditioner Conversion
Date: Sat, 24 Jun 2000 03:56:22 -0400

I've just completed a very worthwhile conversion on my MH.  It came
from Itasca equipped with excellent GM dash air conditioning but
Itasca chose to use the P-O-S York piston compressor.  This is the
compressor you came to know and hate in the 70s and 80s Fords.
Heavy vibration, short belt life and poor cooling.  Because of the
relatively weak mounting bracket, my compressor shook like a dildo
on speed and ate belts at a rate of one every third or forth trip.
I decided to convert the system to a modern rotary compressor.

I chose to use the Sanden SD-510 compressor equipped with #5 (flare)
backing plate.  This is the largest compressor Sanden makes with 6 -
50cc cylinders.  The 4 seasons part number for the new compressor
(remember that we never, never, never buy rebuilt!) is 57035.

Mounting the compressor was very easy.  I had bought a conversion
bracket from an outfit called Jon's A/C Parts in Ocala, Fl (813 748
2328, johnsacpart@aol.com).  This is bracket # 5033.  It bolts to
the pad where the York came from and accepts the Sanden mounting
ears.  The holes were a bit off for the custom York bracket that
Itasca had built but some shims handled that with little effort.
The same fan belt fit this compressor as did the York.

The Sanden has the same size flare fittings as the York but they
extend radially upward instead of pointing toward the front like the
York.  This calls for a 90 degree flare adapter for each port.
Since the catalog lists nothing, I had to improvise.  I bought two
90 degree flare to hose fittings, 4 seasons # 11610 (suction) and #
11608 (discharge).  These are aluminum so it was not possible to
silver solder male flares to the elbows like I normally do so I had
to find another way.  I found that standard compression fittings
would fit on the shank of the fitting after the hose barb was
trimmed back a little.  For the smaller fitting, I had to drill the
bore of the compression fitting a little to get it to clear.  A male
flare X female NPT adapter was fitted to each compression fitting.
The annular space between the fitting and the hose barb plus the
compression fitting was potted in A/C grade epoxy and baked for 4
hours to cure it.  This resulted in a hermetic assembly with no
joints to leak.  There is a female flare that screws to the
compressor and a male flare that accepts the stock hoses.  At this
point, everything screwed together nicely with no leaks and looked
and fit better than the OEM setup.  When I change the hoses to
barrier hoses next  year, these adapters will go away, as the hoses
will be made with 90 degree fittings.  A changeout of the
receiver/dryer, an evacuation and it was ready for freon.

Since my horde of R-12 is still ample, I decided to postpone
changing the hoses to barrier hose and using the R-406a substitute
refrigerant that I helped develop.  (Remember, Friends don't let
Friends use R-134a.)  We'll do that next summer :-)  Charge to a
clear sight glass and see how it works.  Measurements indicate that
the expansion valve needs to be tuned but we'll leave that to next
year too.

The results are IMPRESSIVE.  Within a minute of cranking the engine
in today's 95 degree weather, the discharge air temperature had
reached 50 degrees.  A few more minutes of running at high idle
brought the temperature down to the anti-freeze thermostat's
setpoint.  Driving around town at in-town speeds, whereas before I
had to run both the dash and the house ACs to be comfortable, the
dash air by itself was more than adequate.  This thing ought to
REALLY stroke out on the highway.

In terms of cost, the new Sanden compressor cost me $322 wholesale.
List is around $550 so figure $400-450 from Autozone or the like.
The bracket cost $40.  THe fittings added another $25 or so.  A full
charge of R-12 would cost probably $80 if you have to have an AC
shop install it.

This works so well that it's a no-brainer to do this conversion on
any rig that is stricken with a York compressor from the factory.  I
estimate that the cooling capacity of this system has doubled.  It's
nice to have icy cold air from the dash even in 95 degree weather.
This is a job that required no tools any fancier than a drill and
uses all off-the-shelf parts.  Now I'm kicking myself for not doing
it last year.  Especially after I think about how many belts I've
had to fit to this rig.

John