I'm down to doing the Crapie flop!
Booster does not assist the brakes. Car does stop but it takes a BIG leg effort.
I have 25" Hg on the large vacuum line to the booster, pulsating 14-16" on the small line from the vacuum pump, booster holds 10" vacuum for 10 minutes (may hold more but evacuating a booster with a mini vac is a bit of a job).
I plugged all other vacuum lines: ALDA, trany, locks, ign. switch, HVAC and no change.
I rebuilt the master cyl. the other day and removed 1qt. of brake fluid from the booster. Flushed and bled the brake lines and kept the reservoir tapped off during bleeding.
The only thing left that I have not checked is the check valve in the large vacuum line to the booster.
Advice, alcohol, drugs, shock therapy .... is welcome.