Sorry, did not see this question till now.
When we "clearance" the pads we are taking the pads out and grind off material at the end of the ears of the pads (ie top and bottom if you are looking at them sitting in the brackets) They should be loose enough in the brackets that they are completely free to slide sideways, but not so loose that when you try and push them up and down they have much movement, there is a very fine line between too tight/just right/too loose. Too loose and they will make a clunk every time you change directions and step on the brakes, and will rattle over bumps. Too tight, and the brakes will feel like a seized caliper. If you can not pull the pads out easily by hand, then you found the mose likely cause of your problem. I use a 90 deg die grinder with a roloc sanding disk on it to do this.
And the rear pads tend to seize about twice as fast as the fronts, as they don't always get hot enough to keep them completely dry, so the brackets and the pads tend to rust faster.
I usually do this along with lubing the slider pins, adding moly paste to the backs of the pads and the ears etc etc every oil change, which is every 5k on all my cars.
Christopher "Mighty Mouse" C.
Life's too short to drink bad wine.