I have a 1984 300sd w126.

It will not shut off does anyone know where I can find the fix? Maybe a vacum but which one? Also if it is a vacum where can I find to see if its cracked or broken.

There is several Vacuum related things that can effect the Vacuum Shutoff Valve on the Fuel Injection Pump. If your Brakes are working normal there is a good chance the Vacuum Pump itself is OK.

First do an under the Hood visual inspection of the Vacuum Lined and see if there is any disconnected or there is cracked plastic fittings or rubber connectors.

Next easiest to check is the Vacuum Shutoff Valve on the Fuel Injection Pump located on the Rear Upper 1/2 of the Fuel Injection Pump.

Disconnect the Hose/Tubing; I there is black Oil there that is a indication that you have a hole in the diaphragm of the Vacuum Shutoff Valve. Plug that Hose/Tubing and connect a separete length of Vacuum Hose up to the Vacuum Shutoff Valve.

While the Engine is runnig apply vacuum to the open end of the Hose by sucking on it or using a hand pumped Vacuum Tester like the Mighty Vac. If the Engine shuts off you know the Vacuum Shutoff Valve on the Fuel Injection Pump will shutoff the Engine.

In order to find if there is a leak some where else it is easiest to bypass the other things that use Vacuum like your door locks and the Climate Control.
I do not know the specific colors of those Vacuum Lines so I will let you look them up in our do it yourself section.
The object is to leave only the Shutoff Vacuum Lines connected.

If nothing else is hooked up but the Shutoff Vacuum circuit there is anoter Shutoff Vacuum Valve located on your Steering Colum Lock. This is the one that your key actuates when you turn the Key on or off. There could be a problem with that valve or the Hoses/Tubings that connect to it.

If you have a Vacuum Gauge or a hand Pumped Vacuum Tester (it has a gauge on it) you could als check the Vacuum Pump Vacuum.

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84 300D, 82 Volvo 244Gl Diesel

Vacuum Diagrams
http://www.peachparts.com/shopforum/showthread.php?t=105297

DIY Repair Links
http://www.peachparts.com/shopforum/forumdisplay.php?f=82

http://www.peachparts.com/Wikka/DoItYourSelf

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84 300D, 82 Volvo 244Gl Diesel

Vacuum door locks on a 126 operate with an electric vacuum pump so they are a separate system. So the main leak culprits are climate control, brakes or shut off diaphragm itself. Pushing the far right 'off' button on the climate control will isolate a lot of the climate control vacuum pods from the rest of the system. If the car shuts off with the climate control off, you have a leak in a climate control vacuum pod.

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

Alright, Thanks. Ill look into it this weekend been really busy

Hello there! does anyone knows how much were the1984 MERCEDES-BENZ 300 SD when purchased out of the dealer brand new in 84? Thanks!

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http://i55.tinypic.com/wrxkd3.jpg

What exactly is the issue?

Perhaps you should start a new thread.

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83 SD

84 CD