I have an 85' 300D (603 engine). I recently found a vaccum hose (black) from the Injection pumps' lower side. It runs inside the car behind the instrument cluster and is cut or something. I could not find where this line leads to and how important this line is.


Hope you can help.


Francis

If it ain't broke... don't fix it (bg). What you have is the way it is supposed to be. The line goes to the vacuum proportioning valve on the injection pump. The device is a controlled vacuum leak. Its purpose is to take the high vacuum made for the brakes and leak it off to the appropriate value to correspond to the various throttle positions. If the device just sucked out the side of the valve it might pick up all kinds of trash from the engine compartment. By running the line into the dash it sucks clean air.



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Steve Brotherton
Owner 24 bay BSC
Bosch Master, ASE master L1
26 years MB technician

Great! Thanks so much! Was already getting worried. I had my dash down so I could show it to a mechanic. Guess I'm putting it back now.

Great tip!


Francis