Dr0mme

First time posting, just looking for some advice. I have gone through the forums and haven't been able to solve my issue. I own a 2016 base 370z, the problem occurs when slowing/coasting down and not pressing the brake pedal down to much, a loud squeal happens till I press the pedal down further. Tried simple fixes, new oem brake pads (tried 2 different types since & followed the bedding procedure each time), new shims, dust plate is clear, backing plate appears to be good. I do have slotted rotors, which was suggested could be the issue. Not sure if that is why, wanted to see if anymore had an opinion before I try and swap that out. Thanks, i appreciate it