Power Disc Brakes not working on hard stop?

OK a bit more about the system - picture attached. The calipers are 4 piston and along with rotors are a stock setup correct for a 1967 A body. The MC and booster I believe are also a stock setup, 1967 was first year for dual lines on MC for front/back. There is no air in system as I use a motive auto bleeder kit from Summit ( well worth the $60 - I highly recommend - Motive Products 0100 Motive Products Power Bleeder Kits | Summit Racing). I recall something about the rod adjustment that Dana 67 Dart mentions and can revisit that. Does anyone have good instructions for doing the adjustment? I will Google but that normally lead me back to this site :) Thanks for the good feedback.

67 Dart MC Booster.jpg