When your Rotors Become Warped. You will feel a Shudder when you apply your Brakes. Rotors become warped due to various reasons. Excessive heat is the primary cause of Brake Rotor Warpage. Heat can come from long term Braking down hill. It can also come from Failing Wheel and Brake Components. Rusty, Dirty or Seized Brake Caliper Slides are some of the Failures that happen. Failing or the Wrong application Brake Pads can also cause excessive Heat. When the Brake Shudder starts to happen you will need to at least Machine the Rotors and Replace the Brake Pads. At This point make sure that you investigate the Original Cause of the Failure. Then Repair or Replace the Failed Part. The best thing to do is to bring in your Vehicle to Experience and Trained Brake Technician. They will be able to Diagnose your Brake Problem. They can then make Recommendations to make Sure the Failure does not happen again.