Rear Brake Vibration and Uneven Pad wear

[chumanji9]

My CX9 is at 64K miles. I noticed during high speed braking the rear would vibrate and make scratch noise. I went ahead and replace both the rotors and pads. During my replacement I notice the both the inner pad had more wear than the outter pads. And both inner pad had more wear on the leading edge than the trailing edge (wearing at an angle). The outer pad is perfectly even. I didn't notice anything strange about the rotor...I am not too experience in this matter. I also check the caliper and didn't see any leaks. The slide pins seem to be fine, the bottom pin's lube did seem to gum up a bit, but was not stuck. I did clean and re-lube the pins and it was a lot smoother now.

My question is what causes the inner pad to have more wear and wearing unevenly at an angle? I am just afraid I didn't fix the root cause of the issue and it would come back again.

 

[just_phil]

Inner pads always wear more than the outer ones in a properly working floating caliper design, since the piston pushes on the inboard pad and makes it touch the rotor before the outboard pad. That's why those wear indicator are always mounted on the inboard pads. As for why the leading edge is worn more, that I have no idea.