I'm involved in another rear brake replacement/repair project because of rust. This time in my wife's Chevy Malibu. Just like my 2500HD, the rear brake pads began losing contact with the rotor in large patches. The winter road de-icer deposits a film on the brake pads, causing a loss in contact with portions of the rotor. The progression first causes a loss of braking effectiveness, then over time significant wear of the brake pads as that small contact patch wears away, exposing the pads to a badly rusted/pitted rotor. This process of rusting brake components produces a big safety problem. They need to either make parts that don't rust, or use a de-icer that doesn't cause rust.