Been looking for an article I saw on how to disable/remove the basket of snakes that M/B put on the valve cover of my 83 300D I'm referring to the white vacuum switches and the small vacuum hoses under the black box on the valve cover. How can I completely disable this and what will be the effect?

I'm trouble shooting a hard downshift issue on my 300D and it is pointing to that area. The door locks, shut off switch, climate control, vacuum reservoir system all hold vacuum fine, and I'm getting a steady 21-23" of vacuum at the main vacuum line, so.......

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2012 Mercedes ML350 Bluetec 91K (hers)
2005 Corvette 55K (fun car)
2002 VW Jetta TDI 231K (mine)
1998 Volvo S70 T5 Turbo 196K (kids)
1994 Ford F150 4WD 249K (firewood hauler)
1983 Mercedes 300D 376K (diesel commuter)

pretty sure on your 83 that entire basket of snakes can be removed. you can definitely at least plug the vacuum line going to the EGR.

but looking at the diagram for your engine, this is what i'd do: from the line coming off of the main booster line, run it down and put a Y splitter on it (one line into two.) attach one leg of the Y to a dashpot, then run a small line from the dashpot to the port on the top of the VCV on top of the injection pump. to the the other leg of the Y splitter attach the line running to the transmission. from the side port on the VCV run a line into the passenger compartment, but don't plug it because its a vent.

note that i had a hard downshift on my transmission and fixing the vacuunm problem eliminated it. i think that goes contrary to what i had read here.. that vacuum shouldn't affect the downshift

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1981 NA 300D 310k miles

The timing of the shifting is controlled by the Bendex (throttle) cable adjuster, while the softness (or lack thereof) is controlled by the vacuum if I am not mistaken. I disabled all the vacuum lines today to the box on the valve cover, as well as the EGR, and it made no difference as my plastic paddles that run off the modulator were beyond worn out. Things look a little cleaner in there now.

Do a search for "EGR delete", or start a new thread asking for that in the subject.

That may/may not help with shifting. That War-and-Peace length thread is here:

http://www.peachparts.com/shopforum/diesel-discussion/158216-its-critical-how-you-set-your-transmissions-vacuum-system-your-diesel-mbz.html

You are correct. Although I always thought it was called bowden cable. Bendix was a manufacturer of brake calipers among other things.

The cable control shifting timing and the vacuum modulator controls softness/harshness of the shifts.

Most of the cars can do without these 3/2 valves on top the valve cover. simply plug the supply line that goes up to it and re-route line.

My SD's are very simple. All I've got is a T on the top of vacuum control valve on the back of the IP. Black line goes to transmission, clear line goes up to brake booster line.

Another T on the side of the vcv, one side of the T is blocked, one goes up into the firewall somewhere I think.

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82 300SD 145k
89 420SEL 210k
89 560SEL 118k
90 300SE 262k RIP 5/25/2010
90 560SEL 154k
91 300D 2.5 Turbo. 241k
93 190E 3.0 235k
93 300E 195k

egr 1983 MB SD - YouTube

My coupe has the same set up, I left the black box on, but the plumbing is the same.

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83 SD

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