Jim, why did you suggest the replacement of a master cylinder and wheel cylinders without evidence of failure and state that master cylinders are often "bad" out of the box, then discredit the possibility of failure in another hydraulic/mechanical component?

I am quite certain what Dennis will find when he pulls the seats, and I know why the system was unable to pump up and bleed properly.

And yes, loss of hydraulic fluid from one wheel cylinder can indeed result in the loss of all braking in certain conditions. I've had that happen twice over the years. Once in rush hour a.m. traffic, once in the garage after winter storage. There is a reason that "parking brakes" have also been called "emergency brakes".

After tearing down several "good" master cylinders recently and seeing how much sludge accumulates in the pistons and bottom of the reservoirs, I will now flush the entire brake system every time I service any hydraulic component.