Brake Rotor Grooving 2005-2006 Grand Prix With Crossed Drilled Rotors - keywords disc groove machine

This PI has been superceded to update Model years. Please discard Pic4103.

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Some owners of 2005 - 2007 Grand Prix GXPs may comment that the brake rotors appear to have circular grooves on the machined rotor surface that are aligned with and are the same width as the cross drilled holes. This condition is usually discovered when the customer is cleaning their wheels and is not associated with any braking abnormality. This wear pattern is normal for the cross drilled rotor design and occurs due to the interface of the rotor holes to the brake pad friction material. Additionally, the brake pad friction material will also show the same type of grooving condition. This condition alone will not cause the brakes to squeal or pulsate.

Do NOT replace or turn cross drilled rotors for this condition just to change the appearance. If you turn or replace the rotors for this condition this appearance will return in about the same amount of miles as it occurred the first time under the same type of usage. If the brakes are pulsating or have excessive noise/squeal follow the normal diagnosis and repair procedures for these conditions.

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.