the break petal is not spongy at all, the breaks work 100% perfect almost all of the time but maybe 1 out of 50 times trying to use the breaks there is nothing at all, they go right to the floor, pump them a few times and they are normal again

also there is no air in the system because i have bleed the breaks way to many times and took it to a brake king and had them bleed the brakes with the vacuum method

the master cylinder is good because there is a new one in the car because of this problem and i thought it was that at first

and no fluid is leaking, after putting the car all on cardboard and pumping the breaks and driving down the street and back on the cardboard and no leaks and the level is the same

 

ok got a new proportion valve and tried that, didn't change anything at all.

started all over taking the master cylinder off, re-bleeding it, putting it back in and bleeding the whole system again and no change still, any help here?