Vacuum / not turning off problems
 

Hi, I am recently having trouble with my 83 300D not turning off when your turn the ignition off. I have a 76 Euro to test/compare with and I just have a few questions that I have not been able to find on the forum. First off I read that if the turn off valve does not hold a vacuum that it is bad. The turn off valve does not hold a vacuum but if I apply a vac on it via a mighty vac it turns off. Do I need to replace this valve? It will turn off if I apply a vac to the brown line going into the car or dirrectly to the turn off valve so I think the switch is OK. I think the problem is a bad vac pump. On my 76 I'm getting around 22.5 in Hg. and on the problematic 83 Im getting 4-8 in Hg. I have checked all of the lines to make sure there are no leaks however the line going to the ignition is open when the car is running. Is this normal? Another question I have is: I think the yellow goes to the door locking system? I know the brown is for the turn off. What is the green vac line? OK thanks for the help, Alex

Green is for HVAC controls. Here's a link to some information on the vac system.
http://www.dieselgiant.com/mercedesvacuumtroubleshooting.htm

I would disconnect the large Vacuum line at the Vacuum Pump itself and test the Vacuum output there. If you are still getting 4-8 in Hg the problem is in the Vacuum pump.

If pump is too weak doesn one have to do manual shutoff every time or is there a way around this,also would brakes be affected?

No vacuum pump = no vacuum assisted brakes:eek:

To shut off you can run a vacuum line into the cab and suck on it when you want to shut down, most find it easier to replace the shut off switch:rolleyes: