1972 3/4 front brake caliper/ pad?

[Daves72'GMC]

Help! trying to figure this one out.I was driving my truck yesterday and heard a clicking noise coming from the left front wheel ,so when I got home I removed the left front wheel and the outter pad (closest to the wheel)has two tabs that fit over the caliper when installed and when I rotate the hub /disk assembly the pad moves up and down slightly causing the noise.I had replaced the calipers when I restored my truck.Do you think something is wrong with the caliper or is the pad not fitting right? Thank you Dave