1994 Chevy Blazer Have to pump brakes to get pressure and l

I have a problem my 94 full size blazer has some brake issues. I been noticing a spongy brake. Pedal going further to the floor and the brake light comes on and stays on. I have replaced the front brakes and found a leaking wheel cylinder on the RR. I have replaced all that and bleed the brakes and still spongy brakes and the light comes on I have to pump the brakes to make them work with good pressure. The light stays on and i have to kick the pedal and it goes out. i have no vaccum leaks or fluid leaks. I have replaced the master cylinder and front brake pads and RR wheel cylinder. Up in arms and sick of pumping brakes to stop any suggestions would help out tremedously.

Thank You
Jason