Vintage Cars: 1983 w123 300d turbo w/vacuum door lock issue., master brake cylinder, vacuum valve

Question
Noticed when engine failed to shut down.  Engine shuts down normally when driven a short whil with doors locked.  Locking is inoperative unless engine runs a short while.  the locks then will operate with the rear passenger side door being the last and slow to operate.  Until I get the time to check out further can I and if so how,plug any line in the system to disable locking and have normal function otherwise?  Any suggestions are most appreciated.
James Leftwich
Dallas TX


Answer
the leak in the vacuum can occur if there is a crack in any line or a bad valve.  On the W123 the best place to start is at the vacuum pump,make sure you are getting vacuum,  follow main line from there to fire wall and master brake cylinder, look for a break in any of the lines there. Next to the main vacuum valve in the drivers door and then onto the resevior.
Not easy to just plug one line as they are all interconnected.  A mityvac is great to have when testing these systems

good luck