Worn brake pad...

[SenseiSkins]

I have one of those in my room

[Al Skierkiewicz]

I agree with Dan on this but would like to go a little further. Your picture shows a pad worn through to the backing plate. That means metal against metal on at least one of the rotors. It is possible you have worn through the critical depth of allowable metal for safe brake operation and it is likely that if you just replaced the pad, you have compounded the problem. Since you did not have the rotor turned and faced, you have less than optimal contact on that face and the original problem still exists. You have either a frozen piston or frozen caliper mounting bolts, so the caliper does not retract after you apply the brakes. This leaves the pad in constant contact with the rotor, raising the heat of the assy and causing temperature related failures of the brake fluid, rotor face, caliper piston seals, etc. With that being said, a brake shop needs to asses the damage, replace or repair the defective caliper, pads, and rotor and the fluid needs a flush.