I'm helping a friend in his attempts to make the A/C in his '85 280 SL work. When we started, the system was dead empty, but the compressor casing was dry around the shaft seals and it ran quietly when pressure switch was bypassed briefly with the dash controls in A/C position. Found an obvious leak in the condenser, so we are replacing the condenser and drier with new parts. All of the dash controls work correctly. Once the new condenser and drier are in, we plan to evacuate the system thoroughly and charge it with R-12. (I am hoping to get away with not messing with the evaporator or expansion valve.) Is there anything else I should check or replace before we have it charged? Thanx in advance for any advice.
Colin

The only real question I would bring up is how much oil to add. Since there isn't any history one can not know how many times freon was added only to have freon and oil leak out. I would probably add a little more oil than the component guide would say. I imagine this would be around 1.5-2.0 oz.

Flushing all the system to remove all the oil would require removing the expansion valve. The expansion valve is outside the evap case and not that difficult. Removing the oil would allow a total refill which is the only real way to know. Unless you are real sure of your flush technique I would just add an extra oz.

If you are going to this much trouble, why not replace the Compressor and receiver- drier. I believe this car uses the York comp. and is only $100.00- reciever-drier $40.00. And why not convert to R134a You can get the conversion kit at Auto Zone for $34.95 and it comes with fittings.charging hose,all the oil needed and 3 12oz cans of R134a. I have converted two of my cars to R134a. On one car the air comes out at 38Deg.F. The other at 42Deg.F. Bill Lewallen

Thanks for the replies. We are, in fact, replacing the receiver/drier. The compressor seems fine, so unless we find leaks, I see no reason to replace it. We'll vac it down thoroughly, add oil and R-12 (the R134a is less efficient in a system designed for R-12, and this system is marginal even when in good order) and see how it cools. I have a gut feeling it'll work fine, and I'll let y'all know how it turns out.
Colin

Put the condenser and drier back in last night. (The condenser is a ***** to install without removing the radiator.) Vac'd it down and charged it with R-12/oil today, and it's cool as a cucumber, with the dual temp wheels actually functioning as they're supposed to! A miracle! Thanx for the input, Steve!
Colin