Just had the brake clicking or chatter on my A6 after I switched out the front pads. Did everything the way u r supposed to except I remembered the old inboard pads were hard to get out and the new ones slipped in. I ended up taking the assembly apart again and removing the inboard pad. I spread the 3 clip arms to tighten up the fit within the caliper piston hole and that solved the problem. The factory setting on the inboard pads may not be enough to "snap" them into the caliper piston hole and hold them snugly. If they are not snug they may chatter. Hope that helps
Pk

 

Just had the brake clicking or chatter on my A6 after I switched out the front pads. Did everything the way u r supposed to except I remembered the old inboard pads were hard to get out and the new ones slipped in. I ended up taking the assembly apart again and removing the inboard pad. I spread the 3 clip arms to tighten up the fit within the caliper piston hole and that solved the problem. The factory setting on the inboard pads may not be enough to "snap" them into the caliper piston hole and hold them snugly. If they are not snug they may chatter. Hope that helps
Pk