Hi this is my first post and after lurking on this forum for sometime....I finally was able to scratch my itch and bought a 80 300SD with 280K miles.

After changing out all the vacuum lines under the hood (including the 3 &4 ways) my tranny shifts better but I can't lock the car. When the car is running, all 4 door locks work (go up and down) as soon as I turn off the car I can't push any of the lock knobs down.

Although I haven't made it inside the cabin fixing any vacuum lines, could this be the cause of not being able to push the knobs down when the car is off?

Thanks