Vacuum diagrams and photos from the search

[trontek]

function have not answered my question regarding the line going from the vacuum control valve(IF i've even got that straight in my mind) to my modulator valve. On my '81 300SD, the line is connected to the 'Y" that comes from the main line from the pump to the brake booster. That 'Y' is also connected thru what I thought was a one-way valve(but I think I read was something to smooth out the pulses in the available vacuum ? ) to the top most port on the control valve.

I would appreciate if someone would identify the top and lower ports on what I have called(in my ignorance) the "vacuum control valve".

The line going out the top right goes to the modulator. The line going out the bottom right comes from the line connecting the pump to the booster. The bolt is plugging up where the line to the box on the valve cover was connected.