I recently replaced my aftermarket brake pads and rotors. Now, the car shakes terribly when braking at speeds over 50 MPH. At lower speeds, I can feel pulsations around 14 to 30 MPH, but only while stopping downhill. I did not have this problem before replacing the rotors and brake pads. The rotors are slotted and drilled, with all eight ceramic brake pads.
It sounds as though you may have a warped set of rotors. This is not that uncommon when replacing rotors. Furthermore, the surface where the rotor mounts to the spindle should be clean; if the area has a build-up of rust, then the new rotor may not be setting flat. Most likely, the new rotors are warped, in which case you will want to have them swapped-out with a new set; hopefully your parts supplier will be amenable to this. I recommend that you have a mechanic, such as one from YourMechanic, come by to check the rotors, and run a thorough diagnostic on your shaking while braking issue.
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