So I am chasing down vacuum leaks in my 300TD wagon. Here's the quark. The door locks don't work properly so I figure there is a leak in that system. So to eliminate that problem for the short term I plugged the vacuum lines that come off the drivers door just before they split to go to all the other doors (the yellow line with the green stripe and the yellow line with the red strip). And now my tranny shifts a little smoother, BUT when I turn the key off it doesn't shut the car down. It didn't do this before I plugged the door lock lines. Previously a couple of times it would keep running for a few seconds then turn off, most of the time it wasn't a problem. But this time I had to use the stop lever. My breaks seem to work fine. Does this mean I have other leaks in front of the firewall or did I do something inadverntely by plugging the door look lines.

Thanks

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I would recommend plugging the door lock vacuum supply line that is just forward of the firewall. It usually splits from a four-way connector at a yellow check valve. That should eliminate all vacuum to the door locks and vacuum reservoir. At the same connector, check the brown line; it supplies vacuum to the the shut-off actuator.

You will need to get a MitiVac hand vacuum pump -- any auto parts store will have one. This will allow you to test vac systems, and it has a nice guage.

There are many causes of low vac on these cars, you really need the pump!

Check vac in the main line, test for leaks, examine the plastic part of the main vac line for cracks (they tend to get brittle with age), and check ALL the small rubber connectors on the hard plastic lines -- very likely, most or all of them have gotten rock hard, meaning they leak.

Also check for clogged holes in the nipples on the main line. Do NOT drill them out, please, they have a calibrated orifice in there to prevent excessive vac loss in the main line from broken hoses.

Peter

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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

I've got a mighty vac, and I have found that the door locks are leaking somewhere. Didin't get the time this weekend to tend to the rubber connectors, and check all the lines in the door lock system.

Is the line for the shut off acuator between the firewall and the where I plugged the door lock system?

Thanks

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The shut-off line does not connect directly to the door lock system. But if you created another leak when you disconnected the door lock vacuum lines it could affect the shut-off.

Alrighty, so I have more leaks to tend to.

Thanks

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It sounds like the lines that you plugged are downstream from the vacuum switch in the drivers door. You can isolate the entire door lock system by plugging the line in the engine compartment, as I described earlier.

Door lock line is yellow hard plastic, engine shutoff supply is brown, servo line is brown with blue strip, ACC supply is green (I think), EGR and tranny control lines are white. The green, yellow, and white lines all connect on the plastic fitting on the main hose from vac pump to brake booster, but the brown line is sometimes separate (don't know on that model). Use the MitiVac to see that all circuits are holding vac.

Disconnect the yellow plastic line from the main vac line and plug the main line fitting, this will "fix" any leak in the whole lock system.

The usual cause of door lock system leaks is bad diaphrams (four in each door). These cost about $5 each, and replacement isn't bad once you get the door panel off. Other places that leak are the driver's door switch (test by plugging the lines with colored stripes, must hold vac at all positions then), the rubber fittings on the reservior tank under the left front fender, and line breaks, usually in the bottom of the doors or in the rubber boot at the hinge.

It's very easy to dislodge the vac shutoff line from the servo on the injection pump, by the way.....

Peter

__________________
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!