I am pasting part of your comments into this reply. This situation is fairly descriptive of a piston binding in an oversize bore when brakes are applied and spinning rotor transmits some angular movement to the pad and thus the piston, cocking it in the bore and causing it to bind. Your little test((When I tested the wheels before the second test drive ( jacked the car up...pressed on the pedal and released the pedal-the rotor was free...but during the drive on the road it did not release..)) demonstrates this fact. Good call...
2000 Dodge Grand Caravan SE