Some vehicles may exhibit grooves (1) in rear brake disc plate(s), as shown below. This concern is mostly found on new or low mileage vehicles, when the brakes are new. The grooves may be caused through abrasion from the accumulation of metal particles from the rear brake disc plates. The metal particles get caught between the brake pads and disc plates causing groove damage. To eliminate this concern, the disc plate surface honing process has been changed to reduce metal particle formation.
