THE REAR CALIPERS USUALLY FAIL IN THE MANNER YOU DESCRIBED BECAUSE OF A BAD MASTER CYL. VALVE,THE VALVE STICKS CLOSED AND WON'T ALLOW FLUID TO RETURN FROM CALIPERS ,BRAKES DRAG,PRESSURE BUILDS,HEAT,SMOKE, FADED PEDAL,EMPTY WALLET.
IF YOU HAVE NOT REPLACED THE MASTER CYL. YOU MAY BUY EVERYTHING AGAIN!!
M.F.