I recently installed new Brembo blanks with PBR/Axxis ultimate ceramic pads on all four corners of my 02. They started great, but after ~250 miles, the passenager side now makes an ugly metal grinding sound whenever brake is applied. I checked again today and the installation seems to be okay. I didn't install the hardware kits (shims and stuff) since I forgot, could it be the cause? I thought it could be the pads, but the driver side is quiet as ever. The braking force is still good, just the noise makes me stick out like a sore thumb in the traffic pack, and I prefer being low-keyed. So what might cause the sound? Please help with any inputs and solutions.

 

you probably should have left the hardware kit or put in new ones and but brake grease on all sliding points...