Can't bleed air out of rear brakes

I had this problem on an explorer that a customer did his own brakes on.he brought it in with the same complaint,Turns out he did his own calipers and mounted them on the wrong sides ,putting the bleeder below the brake hose.this was an '03 with a drum p brake.I don't know what setup you used though

X2^ did the disk brake conversion on my demon using 79 volare calipers and couldnt get the fronts to bleed. Turned out the bleeders were on the bottom and was creating a cavity of air above them but due to the brake hoses i had to leave them mounted where the bleeder was on the bottom so i just took the calipers loose turned them to where the bleeder was on top then put a 2x4 in the caliper and bleed them that way. Problem solved