I drive a 2014 Nissan NV2500 HD. I had the brakes and rotors replaced last January (2017) at about 50,000 miles. In November I replaced the front brakes with GT carbon composite brakes (police car/heavy duty truck). They are fine. My problem is the back brakes. They squeal and sometime grind bad. It sounds like the subway train. It looks bad showing up to a customers house like that. In December I had Midas replace the back brakes and they reconditioned all 4 rotors. It did nothing. 2 days later people are asking if I need new brakes. I replaced the back brakes again but this time with GT carbon composite brakes about a month ago. It is still bad. I took off the tires and looked at the rotors with my dad and a guy he works with. My dad used to work on B-52s in the Air Force and he always does his brakes and such with the guy he works with. Everything is greased up and looks good. Rotors look smooth and no discoloration. When I first bought the van (it had 30 miles on it), the brakes were noisy. I took it back to the dealership at 5k and they said everything was fine. I just had noisy brakes (which I said I didn't spend $30k on a van with noisy brakes). Should I replace the rotors or could it be the calipers. I'm at the point of replacing everything but I don't want to spend the $ if I don't have to .