My rear rightbrake is gone

I drive a 2007 Hyundai Santa Fe that currently has 10,300 miles on it. I live close to where I work, so the daily drive doesn’t put many miles on. A few months ago, my rear brakes were squealing like a couple cats were back there, but only when I took my foot off of the brake. I took it to my regular mechanic and he said they looked perfectly fine except they were dusty. Last week, I took it to my mechanic for inspection and he called mid-inspection and said that I had no right rear brake left. Nothing. The left rear was worn down about half way. I called the Hyundai dealer where I purchased my car and they suggested I have it towed in. Being that the brake warranty was up in December, this wasn’t normally covered. But my brake disappearing wasn’t normal either! The manager OK’d the repair for free. The mechanic said that “the brake rusted into the slide.” Like I know what that means?! He said that I didn’t drive my car enough and that the brake just rusted away. Is it true that this can happen or is he feeding me a line of bull?

Yes, it can happen. The brake caliper is mounted in such a way that it moves on a slide, or pin, slightly as the brake is applied. This evens out the brake force on both sides of the rotor. If the caliper slide gets rusty the caliper can’t move and one brake pad will do all the work and wear out rapidly.

I just had the exact same problem with the rear brakes on my Subaru, which often sits for a week or two at a time between uses. The corrosive effects of winter road salt exacerbate the problem.