What might be causing a clanking sound when I hit the brakes for the first time? on 2005 Mazda Tribute

It only happens after the car has been sitting. I have had both the front and rear brakes replaced and it still does it. And it only does it the first time I use the brakes. It is one quick sound like something is slipping into place.

Asked by for the 2005 Mazda Tribute
Late answer , but what the heck........ it is the brake pads shifting in the caliper bracket. If it was anything else , then I hope the person that did the brakes for you checked their work.