All good advice. I can tell you that when new (1983) this AC was the best I've ever experienced and that is part of why I kept the car (hot and humid Texas summers).

I now have (and I suspect you also) vacuum issues that are not permitting the AC doors to go the their proper positions. I'll be removing the dash soon and replacing/repairing all vacuum pods.

If that doesn't get me back to like new AC performance, I'll be selling the car. Anyone interested in a 1 owner, 215k mile, 300D turbo?

Above all, stick with R12 as the refrigerant.

__________________
Charles
1983 300D, bought new, 215k+ miles, donated to Purple Hearts veterans charity but I have parts for sale: http://www.peachparts.com/shopforum/mercedes-benz-cars-sale/296386-fs-1-owner-83-mb-300d-turbo-rebuild-parts.html

I've been looking all over for this information. Thanks! It should be a WIKI (I think that's the right term) especially if you added trouble shooting guides for the diagrams.

__________________
Charles
1983 300D, bought new, 215k+ miles, donated to Purple Hearts veterans charity but I have parts for sale: http://www.peachparts.com/shopforum/showthread.php?t=296386

WIKI or Sticky....

__________________
1980 240d ,

chain elongation, cam marks reference:
http://www.peachparts.com/shopforum/diesel-discussion/10414-help-i-need-check-stretch.html

http://www.peachparts.com/shopforum/diesel-discussion/305365-9-degrees-chain-stretch.html

evap fin cleaning:

http://www.peachparts.com/shopforum/diesel-discussion/156207-photo-step-step-post-showing-w123-evaporator-removal-1983-240d-1982-300td.html?highlight=evaporator

A/C thread

http://www.peachparts.com/shopforum/diesel-discussion/297462-c-recommendations-mb-vehicles.html

Troubleshooting the system could be troublesome. You've got electrically controlled vacuum switches that take inputs from different sensors.

My recommendation for the primary culprit pod is the defrost pod. If that one is leaking it'll affect the center pod by dumping the vacuum. It also has two diaphragms.

You don't need to pull the dash to get to most of them. I'd recommend starting small and checking the foam tube. Pull the glove box and look left. The foam tube connects to the blower motor. No/rotten tube = no airflow across the sensor. I replaced mine with foam pipe insulating material.