[06.325ci]

Hey guys another simple question to hopefully get some options. So i just recently installed new brake pads and rotors, but now every one and a while after i apply the brakes i hear the grind kinda sounding like a moan. I remember putting a small layer of lubricant on the back metal of the pads if this helps. I never hear while or before i apply the brakes its always after and stops when i pick up speed or until it just dies out. Thanks in advance!