Once I got under the car, I could see a quick disconnect on the suction side of the compressor. Hopefully this means the system has been converted over to 134a. There is no sticker under the hood. The compressor is a York made by Diesel Kiki of Japan. P/N488-22027. I've Googled this trying to find some specs on it. Haven't had any luck. Any suggestions on where I might find some specifics on this compressor?

Thanks
1987 240DL

If you are using R-12, you will probably be making connection at the schrader valve on the compressor. Look for the one associated with the fat hose going to the firewall - that's the low side - toward the fender on my car. Yeah I would much rather connect someplace high and dry (like at the dryer) than reach way down there, but unless your system has been modified, you don't have that option.
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Art Benstein near Baltimore

It’s not the fall that kills you; it’s the sudden stop at the end.

You could try a 134a retrofit kit and it will have the fittings you need. They should be standard R12 fittings, and I am sure you will be useing 134a so the kit will be your best bet.