Brake pads destroyed

[johnmr12]

I found half a brake pad on the floor in my garage so I removed the wheels and I found both the inner and outer pad material on the starboard side had been torn off the metal housings. The inner metal housing gouged up the rotor surface pretty bad and was actually bent. The caliper piston was extended way out obviously. The port side was fine. These pads were about two years old and had plenty of pad still left when this happened. I called the supplier to see if they knew of a defective batch of pads maybe, and they said no. They said the manufacturer was very reputable, so now I have to figure out why this happened. The only theory I have is that the caliper piston was pushing on the pads all the time, causing them to get extremely hot. I was able to loosen the bleeder screw and retract the piston so I know its not frozen. How can I test the system so I don't destroy another set of pads.

[billnorman1]

Best check the port side. If the starboard caliper is free to travel and it overheated, either there's a ridge on the support bolt so it won't slide or the master cylinder is not letting the fluid back in and the port side is frozen.
You might also check the starboard bearing clearance just in case it is radically excessive.
I just used two of my three free guesses, anybody else have a good guess?