Re: A/C Retrofitting

["R. Cummings" <cumm@flash.net>]

At 10:41 PM 10/5/98 -0400, you wrote:
>Thanks for the advice, I guess evacuating the system is the sticky point.
>Kind of hard to rig a vacuum pump. Actually my car is an '85 4000S. It
>seems that Audi put the same air conditioner on it as the Quattro, It has
>a two cylinder York compressor and a respectably large receiver/dryer. I
>am very glad to see that it costs so little, my parents paid $183.00 for
>theirs! The leak seems to be from the compressor front seal. Is it a
>possible do it yourself job?
>
If you are not sure where the leak is, you need to have an A/C repair place
put a little R12 in and leak check the system. They will then recover all
the R12 from the system. Even if you are sure only the shaft seal is leaking
the law requires that the R12 remaining in the system be recovered and not
discharged to the atmosphere.

Then you can remove the compressor and R/D. You can try to have the shaft
seal replaced at an A/C repair house (definately not a do-it-yourself job)
or buy a rebuilt compressor and clutch.

You can install the compressor and R/D making sure all "o" rings are
properly lubricated and all joints are properly torqued.

You need to have added to the compressor the correct type and amount of oil.
You will use PAG or ester oil with R134a or mineral oil with R12.

You then need to go back to the A/C repair facility, and have them evacuate
and charge to the correct level with R134a or R12. The correct R134a charge
is 10% less than R12. They should leak check the system after charging.

If you recharge with R12 you are done. If you recharge with R134a, the
charge ports will have changed to attach the R134a hoses, the system will
need to be labeled showing type and amount of refrigerant and oil. A high
head pressure cut off switch is required with R134a (I believe that switch
is already in the 4000).

The performance of the system with R134a is not necessarily poorer than with
R12 but it does run at higher pressure. If the condensing is marginal (and
almost all European cars are) then you need to improve it. This is usually
done by mounting another electric fan in front of the compressor with a
relay controlled by the A/C switch. These fans are available at most auto
parts houses.

Bob Cummings 87 Coupe GT