This is a 47ooo mile very original car.
The front drum brakes will not lock up, they work but not effectively enough. In a normal stop on dry pavement the rear brakes LOCK UP 1st.

Everything has been checked. The shoes are new and so is the hardware and brake hoses. The brake pedal has excellent height.

I think this is a prop valve problem but my understanding is that a 4 drum car only has a brake waring light valve but it does no proportioning. Am I wrong?

Anyone know what size the wheel cylinders should be? Front 9 inch drums. Manual brakes not power.