There are subtle differences aver the years but , the basic thing is to bleed off the vacuum signal to the modulator as the throttle is depressed until it reaches
zero as the accellerator touches the floor .

As you say your 1980 shifts fine , it is time to stop screwing with it before you " fix it 'till it's broken " .

The round yellow thing is a one way check valve that should not be open on one nipple .

Testing vacuum devices , valves and actuators , modulators etc. is dead simple : connect a bit of good hose and place your fingers over the other nipples and suck on the hose with your mouth ~ if it doesn't hold vacuum when you p[lace your tounge over the hose end , it's bad .

Or , buy a Mity-Vac tool , it is simple to use and lets you know how well the vacuum pump is working and can be rigged into the tranny's modulator line with a 'T' for proper road testing and adjusting .

__________________
-Nate
1982 240D 408,XXX miles
Ignorance is the mother of suspicion and fear is the father

I did then what I knew how to do ~ now that I know better I do better

I haven't the foggiest as to how many different vacuum systems were used, ask a Mercedes engineer!

I did look into the FSM on 1980, this is what they show, closest to what you've described. It's entirely possible the vac system has been "adjusted" by previous owners.

Good luck.

__________________
83 SD

84 CD

This is the set-up my 1980 300D has, with the side-mounted VCV and 'M' type pump. This diagram is exact.

Ive copied the system over to the W123 280TE when I shoved in the 1980 engine and trans complete....

--Havent yet driven the car but do not forsee any issues with this part.

__________________
http://i190.photobucket.com/albums/z...0TDnoplate.jpg

Alastair AKA H.C.II South Wales, U.K. based member

W123, 1985 300TD Wagon, 256K,
-Most recent M.B. purchase, Cost-a-plenty, Gulps BioDiesel extravagantly, and I love it like an old dog.

W114, 1975 280E Custard Yellow,
-Great above decks needs chassis welding--Really will do it this year....

Don't misunderstand my smart-arse remarks , I do appreciate all the input....

Will play around with it this weekend.

Cheers

__________________


Mac
2002 e320 4matic estate│1985 300d│1980 300td
Previous: 1979 & 1982 & 1983 300sd │ 1982 240d

“Let's take a drive into the middle of nowhere with a packet of Marlboro lights and talk about our lives.” ― Joseph Heller, Catch-22

Is always a good thing as it allows you to learn & make better decisions....

HAPPY THANKSGIVING TO ALL ! .

__________________
-Nate
1982 240D 408,XXX miles
Ignorance is the mother of suspicion and fear is the father

I did then what I knew how to do ~ now that I know better I do better