It can be in your steering assembly. Pitman Arm, tie rod end/s and rubber bushings...I would check under the car while having the friend or wife turn the steering wheel...When you apply the brakes most of your front end suspension will try to move and if it is worn then you can get vibrations and think that they are coming from your brakes. I have had cracked rotors and could not find new ones and I installed used pads in very good condition and never have a vibration on a 126. When I got to where I was going I replaced the rotors.

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James A. Harris