Maybe someone can answer this.

First the situation. I'm working on a 1977 240D manual trans, manual Climate Control (AC has twist knob like the blower). I've tested the CC reservoir and it's holding pressure, however the Climate Control circuit (green/yellow line) doesen't hold a vacuum when the AC is off. When I turn the AC on it has a slow but significant leak.

The Question: What diaphrams/vecuum element controls should this system have? Since it is not ACC there should be less of a snake pit, but this far I can only guess that it has the following:

1) AC vacuum control switch
2) Circulating Air Flap Element
3) Legroom Flap Lever & Defroster Nozzle

Any Input?

Is that a W123? I have a copy of the W123 Air Conditioning FSM at home, and can post some diagrams if you'd like. Although it'll have to wait until Sunday when I get home.

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1983 Mercedes-Benz 240D
Automatic, A/C, Power Sunroof, Power Right Side Mirror
231K Miles FOR SALE MAKE OFFER

Yep. It's the earliest W123 I've seen to date. One of the first 30k to roll off the line. It doesn't even have a second horn or a fuel door lock. The AC compressor is operated via a twist knob, not the scroll dial. Heater and blower are the tyical three twist knobs. It's also a 4-speed manual. Thanks for the help.

The 123s had 3 separate Automatic Climate Control (ACC) systems, yours is ACC I

The info for yours is in section 83-5xx on this web page.

http://www.pauldrayton.com/uploadfiles/merc/Service/W123/Index/Groups/83ClimateControlSystem.html

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83 300D 328k mi (623) Light Ivory - daily driver
82 300D 166k mi (881) Thisle Green - fixer upper
82 300D 282k mi (473) Champagne - parts

Sweet Jesus, that's it!! Only two diaphragms and a bunch of hose. Thanks.