Noise Coming from Rear Left Wheel on Silverado 1500 Single Cab 5.3L V8

What is your question?

For several months non stop, our chevy silverado has been making a noise coming from the back real tires on the drivers side. On both back tires, all new rotors, calipers, and brake pads have been installed new. For some reason, when you go slow such as 5 mph you can hear a noise such as metal rubbing metal. I have hear something called a vacuum plate on the rear tires. but i cant be sure thats what its called. It is possible it needs a new plate or a new caliper or possible wheel bearing.