A couple months ago my brother and I change the front rotors and all the pads on my 'O5 SLK. Instead of the OEM Mercedes pads, we put on ceramic pads. Now I have a horrible brake squeak when I first apply the brakes. After hitting them once or twice it goes away. Not sure if it is due to the ceramic brakes or not putting enough copper grease on the backs. Either way, I'm going to have to get in there and redo. Any thoughts?