Steering Wheel Shimmy Can Be Warped Rotor

There are various indications if your disc rotors are damaged. One of the best indications is if you've been feeling a shimmy in the steering wheel or brake pedal when you apply the brakes. Another indication is that possibly the brake pedal pumping up and down, even slightly, you may have bad rotors.

•   Discs, are the shiny part the brake pad contacts when the brakes are applied. These brake parts can run very hot. If you've ever watched an under the car shot of the front wheels on a race car, you've seen brake rotors turn red and glow.

•   When driving on the street you seldom get the "glow" but the rotors can become hot enough to warp, especially if you drive through puddles of water or snow after making multiple stops and starts. The warping is caused by uneven heating in different areas of the disc.
•   Brake pads are in constant contact with the rotors. If the driver has a foot on the brake pedal, called "riding the brakes", all the time the brakes will wear out prematurely and the rotors will run hotter. This is a bad habit and should be avoided.

•   Towing vehicles and driving downhill in the mountains, or on crooked roads where the brakes are used a lot, can also contribute to warped rotors, especially if there if water, slush or snow on the road. Again this causes uneven heating of the brake rotors . If you experience a slight pull upon braking that can be an indicator of bad brake rotors or brake calipers that need rebuilding because of the brake rotors . It can also be a sign of a low tire. A spongy feeling brake pedal can be caused by excessively hot rotors, which in turn can boil the fluid in the brake calipers. Once the brake fluid has been boiled or is over two years old, it should be changed, as the brake system and the rotors will no longer stop your car safely. Regular drum and disc brake type brake fluid collects moisture and can cause problems with the entire braking system, especially with rotors, if not changed at the recommended times in the owner's manual. Bad brake rotors are not that an uncommon problem. Bad rotors can cause other problems, such as noise from a brake rotor, and the  vibration of the rotors can also be felt in the seat of your pants.
• Rotors can be expensive. Some rotors sell for under $50 while exotic car rotors can go for over $500 for a set of front brake rotors and almost as much for rear brake rotors. Bad brake rotors can be dangerous and any problem with rotors should be checked out by a competent mechanic who is qualified on those type of rotors.