firsr of all i would jack up each rear wheel and spin them by hand to hear for any grinding noises etc...from experience a clicking noise from brakes ususally indicates the pads are loose in the calipers..is the shims still there or broken ?...try reversing then pulling forward usually the pads click due to lifting in the caliper pad housing...if fitting new pads i would gring off any lips on the outside of the discs...plus check the inside of the discs for signs of scoring etc...hope this helps,,,cheers