Brake issue. Master cylinder?

[HappyJack]

Just came back from probably the final drive before I park Rosie for the winter.

Rosie is my 67 Fury III convertible. She has 4 wheel power drum brakes.

About 2 blocks from home the brakes felt weird, and the pedal had a long stroke before anything happens.

So I popped off the cover for the master cylinder and sure enough the rear chamber (for the front brakes?) was empty. But the weird thing is the other chamber is overfull.

A quick look under the car and no obvious leaks appeared. No dribbles from any of the drums. I know I have to pull all the wheels and drums anyway. But why the over full chamber?

Bad master cylinder?
Bad proportioning valve?

Thoughts?

 

[Big_John]

Bad master cylinder?

Probably, but pull the back drums and look at the wheel cylinders, rubber lines etc. I think the fluid is leaking past the seals and filling the rear, but I can't say I've ever seen that happen.

Bad proportioning valve?

Nope... There is no proportioning valve in a drum brake car. People like to call the distribution block a proportioning valve for some unknown reason.