1967 C50 Brake problem :confused:

[WI_Jeff]

I have an ongoing problem with the brakes on my 67 Camper (School bus). Every once and a while when I step on the breaks, it's like stepping on a over ripe banana. I get the same results as stepping on the banana too! This does not happen all the time. Most of the time you can pump them up at the start of the day and they work fine. But it sure makes life "exciting" when they don't work.

I have replaced all wheel cylinders, break lines, booster and master cylinder. I have bleed them, set and reset until I can do it in my sleep. Still the same problem.

It has a single master cylinder and I would like to replace with a dual, but, I can't seem to find one. (I wonder if this would correct the problem.)

I need some help!