After further investigation of my problem I'm 99% sure my problem is caused by deflection that knocks that pads off the rotors. I measured rotor run out with a dial indicator, changed wheel bearings (set them up properly) and I still have the problem. I can pump the pedal to get it hard on the garage floor and then grab hold of one of front wheels and then rock the wheel / the whole car and when I then push the brake pedal it's noticeable softer. Could the deflection resulting in pad knock back be caused by the smaller drum brake spindle diameter and the smaller bearings that the drum brake spindle got? What also got my attention is my 8" wide rims with little backspace putting more leverage and force to the spindle and bearings. Could new spindles with lagers dim bearings offer less defection and keeping the brake pads closer to the rotor even on rougher road surface and tight cornering where I normally feel problem being largest?