Okay I have a 91 xj that i am having brake troubles with

first off things that i have replaced
master cylinder
porportioning valve
calipers
rotors
pad
rear brakes

basically my problem is I press the brake and I dont get any resistance until I reach the floor and the back brakes will lock up, while i am wheeling it will not hold me on a hill so really want to get this fixed before my nxt trip.

I have bled the brakes about 10 times and still nothing
and yes calipers are on correctly

 

Did you adjust the rear brakes after replacing the shoes?

 

Did you bench bleed the master cylinder before installing it?