Brakes: Troubleshoot Warped Rotors
A pulsating brake pedal may not reflect rotor warpage ().
When pulsing is observed immediately upon installation of brand new rotors, verify that they have been oriented on the hubs such that measured run-out is minimized.
When pulsing emerges after rotors have been in service for some time, the problem is likely due to uneven pad deposition (commonly caused by improper bedding, particularly when switching compounds). This can be rectified by having the rotors cleaned up on a lathe or by making several hard stops with cold (abrasive) race pads.
Other common causes of this sensation involve suspension and/or steering components, such as a worn tie-rod.