Recently I fixed the bellows on two of my door lock actuators, and they seem to be holding up well. However, in colder weather, the car does not seem to hold vacuum. Either the check valve in the driver's door is bad or the culprit may be what appears to be an "extra" check valve on the middle line coming from the main valve. Refer to the pic below.

Note the big arrow pointing to the middle line, and the inline check valve. Is that supposed to be there? I referred to a diagram of the vacuum system in the driver's door, and this little bugger was not there. Perhaps the main valve was bleeding off vac, and this was installed in order to retain vacuum. Any ideas?

I guess I will attempt to remove it and see what happens, but I'm betting that my main valve (with the three lines feeding into it) is bad...

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Matt
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1995 E300 Diesel (Die Blau Frau)