1...I bet the shoes are not properly arc'd to the drums
2...I bet the shoes are not adjusted tight enough
3...I bet they need to wear in a bit
4.. The distro block/ warning switch has nothing to do with this, except "make sure it's centered." Used to be a little tool you could buy, you unscrewed the switch, replaced it with this tool, and it kept the piston centered for bleeding
5....Just for grins, have a helper look at the firewall area as you apply the brakes, look for movement, warping of the firewall, etc
A drum brake system with manual master should be a "rock hard" pedal, and that is the end of that story
