Hard pedal

In some ancient mopar magazine, I read that one of the reasons for switching to floating caliper brakes was due to corrosion problems (mostly in the rust belt) and sticking pistons in the KH calipers.
Each piston must move equally to the others, and there was less total movement of the pistons to keep them freed up.
My dad's 76 Volare with single piston discs had one lock up when it was only 5 years old. We did get it apart, and the aluminum piston was not very pretty, but worked fine after cleaning the corrision on it and the bore. It's hard for people to understand just how much road salt was used back in those days. They plowed less, spread a lot more salt. Everyone got where they were going, but your car fell apart in 8 years if you parked it in a garage during the winter.