have now had to clean rear brakes of dust for 3rd time in a year. it seems to cure a short chirping noise when i apply the foot brake from the rear of the car (usually o/s rear). the pads still have plenty of meat on them. the thing i have noticed is that on the end of the calliper piston which was not seized on either side there is a cup with a hole in it that i presume marries up with the notch on the back of the brake pad. this dish will not turn independantly of the piston as wont both sides. considering the fact the piston turns, i think it should but have tried allsorts to free them. seems a shame to replace the callipers just because of this. perhaps grinding the notch off the back of the brake pad and putting copperease on the back of the pad would cure the problem. any thoughts?