I've got an '06 Azera with 145K+ miles -- replaced front and rear rotors/pads about a month ago and noticed that the left rear rim is getting extremely hot after driving even short distances of 5-10 miles. When I say extremely hot, I actually mean that the rim will burn your finger just as if you were touching a hot rotor. I can also smell the pads on this wheel, but there's no smoke. Not to mention my car starts wobbling/shaking at exactly 50 mph, but I've noticed it even at 30 mph (without pressing the brakes) -- the wobbling/shaking may not be related but it all started at the same time, so... I don't feel any loss of stopping power; I'm most concerned with the shaking and the fact that these rotors/pads are practically out of the box.
Took the wheel off yesterday and checked the slider pins -- they seemed absolutely fine, but I cleaned and re-lubed them anyway. Also checked to see if the wheel was bound up on a stuck caliper piston but it spun freely, with minimal resistance. Did a visual check on the piston and it's pretty rusty and corroded, but with the wheel spinning I didn't think this was actually causing the problem. Checked the pads -- hard to describe what they looked like but it wasn't normal and smooth. It was like they were burnt -- they were kind of flaky and crumbling and white-grey colored -- which makes sense if the wheel is getting so hot.
Now what doesn't make sense is that I checked the right rear pads for comparison, and they looked the same! They had the same white-grey color and crumbling, yet the right rear rim has always been normal temperature.
My first thought was replace the caliper but I don't want to scrap the old one unnecessarily. Any ideas???