QUESTION: Almost every time I use my brakes anything more than gently I feel a shuddering in the car and in the steering wheel. I've heard this is because I've gotten the brakes too hot. I just had brakes and tires done a little less than a year ago. What is the fix, and how can I keep it from happening again?ANSWER: it sounds like your front disc brake rotors have become distorted, which causes a shaking or pulsing condition as the brakes are applied.Excessive heat generated during braking or improper wheel lug nut tightening can create rotor lateral run-out, or wobble. With additional driving, rotor thickness variations begin to occur, resulting in pedal pulsation. A tiny amount of thickness variation — perhaps a few thousands of an inch, is all it takes to cause noticeable shudder.Besides being straight and true, brake rotors must be of adequate thickness to absorb and release heat. Wear and refinishing — cutting or grinding the rotor surface to restore smoothness and parallelism — can result in a thin rotor, which is prone to warping during heavy use.It's possible during the recent brake job that the rotors were machined, making them more susceptible to heat damage. Or, if the shuddering occurred soon after the work was done, the wheel lug nuts might have been improperly tightened.The fix for your shuddering will involve measuring your brake rotor's thickness, then refinishing or replacing them. If they are substantially thick and haven't yet been resurfaced, doing so will correct the shuddering. If they have been previously refinished, replacement rotors are the best long-term solution, and are surprisingly inexpensive.Brad Bergholdt is an automotive technology instructor at Evergreen Valley College in San Jose. Write to him in care of Drive, Mercury News, 750 Ridder Park Drive, San Jose, Calif. 95190, or e-mail to under-the-hoodearthlink.net. He cannot make personal replies.