Noises problem
2006 Toyota Tundra V8 Two Wheel Drive Automatic 53000 miles

I drove my trd stepside through deep water, foot or so, 2000 miles ago. The only strange thing it now does is when I am parked, back up with some brake pressure, I get a rubbing sound and a very slight shudder from the rear. Could the brakes have gotten some strange problem from being soaked. No noise or rubbing after driving a very short distance, 10 feet or so.
Performs perfectly otherwise. Help!