I have a scraping/grinding noise that is rhythmic with speed that seems like its coming from my right rear wheel. I Usually dont hear it untill about 5 minutes into the ride. It comes when I make a right turn sometimes but then it will keep making the noise after the turn untill I end up hitting a good bump. The wierd thing is, it completely goes away when I brake. Thats where im baffled. My Backing plates are completely rusted and the right one is half missing from rusting away. Any opinions will help. Thanks

 

Update:

I threw the rear axle up on jackstands and took both of the wheels off of the truck. I was taking a good look at the brakes and I grabbed the right rear caliper and the back end lifted right off the rotor. Turns out my upper caliper bolt wasnt even there. Going to the parts store tommorow and hopefully picking up a bolt and to see if that fixes the problem