Any ideas what might be causing this creaking on the front left brake (watch the attached the video)? The noise occurs on both press and release of the brake. I've replaced the pads and spring, and later the disc, and both times the sound stopped but returned after a short time. It seems to get louder with time and more use.

creaking.mov

 

Caliper piston in rough shape? slide pin not greased up well? What did it look like when you replaced the pads? Did you grease up the slide pins?

 

Yep. The mechanic even polished the pins.