Brought mine to the dealership they can't find the knocking noise. I asked the technician to Test drove it but still can't find the problem. Technician on the passenger side and we test drove it. He was able to hear it, but can't confirm if its coming from the pads or rotors. Its pretty anoying when driving at night when the roads are quiet. You can hear it even with windows close.
I don't think it's that common, i just think it's the actuator. getting them to replace it will be difficult because you're out of warranty, and they're not going to want to pay for it since there's no trouble code and the brakes are otherwise 'fine'. you can sit in some new ones with the service manager and see what he thinks.
I've noticed there is usually a clunk the first time I brake in a new direction. I attribute this to the pads/components sliding slightly in the mechanism. For example, when I back out of the garage, I get a clunk the first time I apply the brakes after moving in reverse. The same applies the next time I apply the brakes after moving forward. I don't consider it a big deal.
