Okay I might have answered my own question.
I have looked at an internal diagram of a dual master cylinder. It seems there is a primary and secondary piston that are not directly connected together, but have a spring between them. So pressing the brake pedal would move the primary piston and then either via the spring or with fluid pressure, the secondary piston would also move.
So it looks like the distribution block / differential valve would block the leaking circuit. And the dual master cylinder would still work as it looks like one piston could still work when the other one is facing a blocked circuit.
Am I on the right track or getting this totally wrong?
Fluid from one system (front or rear) cannot flow into the other. That is the essence of a 'dual' brake system. But if one side of the system (front or rear) has a leak the differential valve doesnt 'block' the leak.
Okay. Engine Stop. ACA out of Detent. Mode Control, both Auto. Descent Engine Command Override, Off. Engine Arm, Off. 413 is in.
-Buzz Aldrin, Apollo 11 LMP
Actual first words from the surface of the moon
Early Fox: 5.0L HO SEFI conversion, 5-speed, 8.8 w/3.27:1 TL, full dual exhaust
1968 coupe - Ordered 12.15.67 Delivered 2.1.68: 8T01T, 65C, 289 conversion, hanger queen
Last edited by Paul1958; 04-15-2018 at 08:17 PM.