I searched and didn't see anything so maybe one of you guys can help me out here.

I've suddenly started hearing this popping sound when I hit the brakes. I haven't done anything to the car so I'm amiss. The best way I can describe the sound is it's like some one is tapping under the drivers side door with a ball peen hammer(not pounding but tapping) every time I hit the brakes. I've checked all bolts associated with the calipers and they are all torqued to spec. The pads and rotors look fine also. Any help would be greatly appreciated....