Just installed posi quiet brake pads x4 and centeric rotors x4 as well. And i did the bedding procedures and lubing procedures as directed by the manufacture. As I begin to engage the brake to come to a stop at any speed it squeals like nails on a chalkboard on the front left side. Took both front tires off and i found the brakes like this,(see below) is that wrong or right and doesnt even matter. (Refering to the metal thing in between the pads.

 

The metal shim should not be cocked like that. It should be straight up and down. Yes that can cause brake noise. Whether or not that is your issue, who knows. Remove and reinstall it then see what happens.

 

How loose is that shim, can you move it around with your hand? The tension on it should be high enough that it shouldn't have a problem sitting vertical.

The vibration must be something else not install correctly, especially if those are brand new pads and rotors. You could try brake bedding: http://www.zeckhausen.com/bedding_in_brakes.htm

 

So my front driver side caliper might be defective. Borrowing one to see if the noise goes away a d ways swap the front pads from left to right and vice versus. Just wanted to give a shout out to RRE for helping me out thus evening last minute.

 

Also wanted to add I had RRE bed them in again and still vibrates, im going to try bedding them again myself.

 

Issue finally figured out horrible pads from centric, getting a refund one way or another, the pads also cause minor defects into my new rotors.

 

Damn that sucks, did you end up swapping in another set of pad (or the old ones)?