brake problems.

i seem to eating up my back brakes like there's no tommorrow? i have replaced all four calipers, porportioning valve, and the master cylinder. i have checked for leaks. none. i have a manual tranny. right before i replaced my back calipers i noticed that they were sticking. and the tires did not spin freely at all. that is why i replaced them. now i have new calipers and still the same problem. the back tires don't spin at all when i have the car jacked up and the e-brake off. wth is the problem?

:feedback: does anyone know what could be wrong? can the e-brake cable be doing this? or am i getting bad calipers?