Shutoff Diaphragm Leaks -- 1993 124

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Jun 25, 2009 | 02:06 PM

Oldwolf

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Shutoff Diaphragm Leaks -- 1993 124

Lately my w124 300D 2.5L has been shutting down slower and slower. Once I turn the key to off it takes 1 to 2 seconds for the engine to slow down and stop.

My first thought was that the shutoff actuator is going bad.

The first step I did was to remove the brown vacuum line from the actuator and the other end from the brake booster line. When I plug up the end to the actuator and use my MityVac on the other, the line holds vacuum great with no bleed down. I believe this means the circuit from the brake booster line to the actuator is tight.

When I put the MityVac directly to the shut off actuator, I can pump and pump the MityVac and the shutoff lever just moves down a bit and comes right back up to the no vacuum position.

When I push the shutoff lever to OFF and plug the shutoff actuator outlet the lever will slowly move up to the ON position.

I assume the actuator should hold a vacuum, correct? This must mean I have a leak in my actuator diaphragm.

I understand that if you put it in backwards you can mess up the engine.

The new style shutoff actuator is made of plastic. Should I look around for an old style metal one?

Thanks-Brad

Jun 25, 2009 | 06:13 PM

Oldwolf

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I ordered the plastic one. Thanks!

Jun 27, 2009 | 06:38 PM

Oldwolf

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Now my car won't even shut off with the key. To keep oil out of the vacuum system I'm not even trying to use the key anymore. The diaphragm should be here Wednesday.