High side is normally the smallwer of the two lines.
Low / Suction side is the larger line.

Stan Wilder
----- Original Message -----
From: "John N. Motlagh" <JNMOTLAG@SPRINTPCS.COM>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Sunday, May 30, 2004 5:37 PM
Subject: Re: A/C charging and maintenance...

> I am about ready to give this a try, however, I am having trouble
> identifying the low side of the compressor.  Even the Bentley picture does
> not look like my compressor.  In addition, the service ports have the same
> threads.  So, standing in the back of the van, looking forward there are
two
> lines. One in the center of the compressor, running to the driver side,
the
> other line is off-center towards the passenger side.  Which is the low
side?
>
>
> -----Original Message-----
> From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
> Stan Wilder
> Sent: Friday, May 28, 2004 8:42 AM
> To: vanagon@GERRY.VANAGON.COM
> Subject: Re: A/C charging and maintenance...
>
> Author/source: Dave Stragand www.projectvixen.com
>
> --------------------------------------------------------------------------
--
> ----
> This is a fairly complete checklist for the conversion based on
> Sanden/Sankyo's own instructions, material gathered from the web, and the
> wisdom of those DMCNews owners who have already completed this procedure.
>
> 1) If the R-12 vehicle air conditioning system is operational, run it at
> idle with the A/C blower on high speed for five (5) minutes to optimize
the
> amount of oil in the compressor.
>
> 2) Recover all R-12 refrigerant from the vehicle's A/C system.  Evacuate
the
> A/C system for at least thirty (30) minutes to a vacuum of 29 in. Hg,
using
> R-12 equipment, to remove as much R-12 as possible from the residual
mineral
> oil.  Don't just dump the old R12 into the air.  If you really don't want
> it, at least let a service station vacuum it out.  They will generally
take
> it very happily, as it is quite expensive, and you won't be polluting.
>
> 3) Remove the compressor from the vehicle, noting the placement of all
shims
> and washers, and the routing of hoses and wires.
>
> 4) Remove the compressor oil plug and then drain as much mineral oil as
> possible from the compressor body.
>
> 5) Drain mineral oil from the cylinder head suction and discharge ports
> while turning the shaft with a socket wrench on the clutch armature
> retaining nut.
>
> 6) Remove the existing R-12 receiver-drier or accumulator-drier from the
> vehicle and discard.  Allow as much oil as possible to drain from the A/C
> hoses. Blowing them out with an air gun on moderate pressure is okay.
> Back-flushing the lines is recommended. Plain old mineral spirits swished
> around in the compressor and backflushed through the lines will remove
> contaminants and old mineral oil. Make DARN, DARN sure that you get ALL of
> it out of the system, and I do mean ALL of it.  Mineral spirits can be
> explosive, but a great many a/c shops still use this technique to great
> effect. I would recommend drying everything out with clean dry air from a
> compressor for quite a while (hey, air is free, right?) Commercial a/c
> flushing chemicals are also available which will do the same while being
> safer, but they can be pricey.
>
> 6) Replace any O-rings on the receiver-drier or accumulator-drier joints;
> check and replace other O-rings that have been disturbed. You really
should
> replace them with the new green ones -- they work very well for both R12
and
> R134a.  If you are converting to R134, new reports suggest that you
do -not-
> need to change all of the O-rings to different materials as thought
earlier.
> However, I would recommend changing anywhere you have disconnected a
joint,
> just to help seal better. They're cheap anyway, and cheaper than having to
> do it again because of a leaky seal.
>
> 7) Replace the accumulator-drier with a new R134a compatible unit which
> contains XH7 or XH9 desiccant. Make sure that you get one with "XH7" or
> "XH9" dessicant, not "XH5" -- there should be a sticker on it stating as
> such.  XH7/9 works just fine with R12 and is necessary with R134's Ester
or
> PAG oils.  As a cross-reference, a 1986 Corvette accumulator-drier is
> perfect. Factory Air brand part number 33191 dryer is ideal, and runs
about
> $55 at AutoZone.
>
> 8) While you have the accumulator-drier removed, now is a good time to
> replace the orifice tube.  Always replace it 'just because'.  The type
used
> on the DMC is just a standard "white" GM orifice tube used for many years
on
> many GM models, and the cost is less than $2. (Any parts counter person
> should know what you mean when you ask for one). There are some newer
> variable orifice tubes claiming to work better with R134a, but I have not
> read very much about them, and I'm a little wary of their claims.
>
> 9) Perform any necessary repairs to the compressor or A/C system.
>
> 10) Using the original refrigerant oil quantity specification, add [INSERT
> QUANTITY HERE] ounces of Ester oil to the compressor. Ester oil is
> preferable to PAG in a retrofit, as it will mix fairly well with any
> remaining mineral oil.  It was originally thought this was not the case,
but
> consensus nowadays is that they mix satisfactorily.  Ester is also less
> corrosive than PAG.  As an additional benefit, R-12 will also work with
> Ester should you ever wish to convert back.  If you follow these
guidlines,
> all you would need to do to revert to R-12 is completely vacuum all R134
out
> of the system and then simply reinstall R-12.
>
> 11) Replace the compressor oil plug O-ring with an new O-ring.
>
> 12) Reinstall the compressor oil plug. The plug seat and O-ring must be
> clean and free of damage. Torque the plug to 11-18 ft lb (15-25 N m,
150-250
> kgf cm).
>
> 13) Change any seals at the compressor ports to new seals.
>
> 14) Reinstall the compressor to the A/C system, paying close attention to
> the placement of shims and washers from step #3.
>
> 15) Disable the R-12 service fittings to prevent any refrigerant other
than
> R134a from being used. You do this by permanently installing R134a
> quick-connect service fittings to the A/C system.
>
> 16) Vacuum the system for AT LEAST forty-five (45) minutes to a vacuum of
29
> in. Hg once the lines are cleaned, the new drier installed, the correct
> amount of Ester has been poured in the compressor body, and the whole
system
> is ready to go. Harbor Freight makes a cheapy high-vac pump for $15. You
can
> hook this up to a spare R134 can adapter hose ($5) to make the correct
> fitting for attaching to the car. And yes, you MUST evacuate the lines.
This
> is the most common mistake people have in retrofitting. If you don't get
> that vacuum down in the system, there is no way the air is going to blow
> very cold.
>
> 17) Charge the A/C system with R134a. Generally, about 5% (by weight) less
> than the R-12 charge amount is required. That means just a little over 2
> pounds for a DMC.
>
> 18) Check the A/C system operating parameters. The system should function
> correctly within acceptable limits of temperatures and pressures -- this
> will ensure that the correct amount of R134a has been charged.  I
purchased
> at a small R134 gauge at Pep Boys for less than $5.  It looks much like a
> tire pressure gauge.  It tells you the system pressure in terms of
> low/good/high/danger. Likewise, they have a small & cheap "meat"
thermometer
> that will tell you vent temps inside the car.
>
> 19) Replace all R-12 compressor labels with retrofit labels per SAE J1660
in
> order to provide information on the R134a retrofit which has been
performed.
> In other words, you really should put a sticker on there that says it's
> R134a.  The recommended places are on the compressor and the accumulator.
>
> Additional notes:
>
> - In extreme circumstances when expected cooling performance cannot be
> achieved and high discharge pressures are experienced, it may be necessary
> to add more condensing capacity to the A/C system.  I believe PJ Grady
sells
> a larger capacity condenser for our cars.
>
> - Sanden has the service manual up for our compressors online at
> http://www.sanden.com/support/servicemanual/index.html
>
> -Dave
> ----- Original Message -----
> From: "zolo" <zolo@FOXINTERNET.NET>
> To: <vanagon@GERRY.VANAGON.COM>
> Sent: Friday, May 28, 2004 12:42 AM
> Subject: A/C charging and maintenance...
>
>
> I would like to ask the Honorable List for extensive advice on the subject
> of the A/C maintenance and charging.  I would like to do it myself instead
> of going to a shop every time I need a system serviced or change a pump or
> change over to a different gas, etc.  I would feel better if I knew all
that
> I have to know about our vans' A/C system.
> I would like to read about the principles and whatever it takes to aquire
> the knowledge.  So, please enlighten me.
> Zoltan