I’m assuming from your statement that it is a four-wheel disc brake vehicle? If so, there may be an adjustment for the rear calipers to keep just enough clearance for the hand brake to lock the rear discs when applied. If too tight, they will drag when warmed up and eventually overheat, crack and fail to assist in stopping the vehicle.
My vehicle’s rear brakes are dragging only when system is at operating temp and when I start to turn the steering wheel. It won’t do it going straight; only while turning. I have already replaced all four brakes and rotors, plus calipers. What can cause this?