Hey everyone. I just have a quick vacuum leak question. My Vacuum locks will not operate after my car has been sitting. All locks DO work after engine shutdown (trunk, gas door, doors) Now, after some time all stays locked except the gas door becomes unlocked. Is it fair to say the my leak is coming from the vacuum actuator or not necessarily?

Either an actuator or the vacuum reservoir in the trunk. Also, replace the check valve, it's possible it isn't sealing after the vacuum from the pump is cut off and is allowing a slow leak to happen. The check valve is a yellow plastic piece near the oil filter in the engine bay, with a single vacuum input and two vacuum lines which will run through the firewall and into the car.

You noted that the fuel door becomes unlocked first. I suspect that might be the area the problem is. In my '83 240D, I found that due to being coated in diesel fuel, the vacuum line running to the fuel door actuator had come undone and because of the fuel, could not be secured back into the receptacle.

Check all actuators to ensure they are connected solidly, as the first step.

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1983 Mercedes-Benz 240D
Automatic, A/C, Power Sunroof, Power Right Side Mirror
231K Miles FOR SALE MAKE OFFER

Where abouts is the resevoir located?

There are two. One above the fuel tank and one inside the drivers side front fender.

'Not sure if I've got the right year 240...But here it is.

Number 5 in the diagram.

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'84 300SD sold
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