Eliminate Rotor Warping

Removal of the rotor is required for lathe resurfacing.

The “rotor” is the disk in a vehicle equipped with disk brakes. When a rotor is warped, a pulsing or throbbing sensation can be felt in the vehicle when the brakes are applied. True rotor warping is a result of the metal rotor becoming distorted. The phrase “rotor warping” also refers to uneven wear patterns that can produce the same pulse and throb as felt with genuinely warped rotors. Elimination of rotor warping, both distortion and wear pattern, requires selection of quality parts, a good break-in procedure, limiting extreme braking and proper maintenance of the brake system.

Instructions

1. Steel rotors are precision-machined to ensure the surface is level.

Install a brake rotor of high metal quality and weight. Higher quality and heavier brake rotors dissipate heat more effectively than those made from lighter or inferior materials. Replacing your stock rotor with a denser, heavier metal will reduce metal distortion from heat damage and allow the rotor to operate at cooler temperatures. Cooler temperatures will not only prolong the life of your rotor but also reduce wear on your brake pads.

2. Uneven rotors can result in tire damage over time.

Install brake pads designed to wear evenly on your brake rotor. Some brake pads may be inappropriate for your vehicle’s braking system. For example, high temperature ceramic pads designed for installation on racing vehicles for extreme braking conditions may cause premature wear of your rotor or poor performance at moderate speeds.

3. A long road without traffic or pedestrians is best for breaking in new brakes and rotors.

Break in your pads and rotors. The break-in procedure varies by pad type and brand. Consult the instructions provided with your specific product. If no instructions are provided, the first 10 to 100 stops should be from moderate speed to a full stop. Allow the brakes to cool between braking and do not clamp the brakes to the rotors during cooling. The break-in process burnishes the surfaces of both the rotor and pad. Burnished, or highly polished, surfaces will ensure that both pad and rotor wear more evenly.

4. Extreme braking on a motorcycle can result in rotor metal fatigue and distortion.

Avoid extreme braking. Braking hard from high speeds can embed brake material in the rotor surface. High-speed braking also creates significantly more heat. Plan ahead and allow your vehicle to slow by coasting when it is possible and safe to do so.

5. Drilled rotors are used to dissipate heat more rapidly.

Do not clamp the brakes after extreme braking. Pads clamped to super-heated rotors will transfer brake pad material to the rotor. Transferred material leaves a bump on the rotor that interferes with smooth contact. Over time, the buildup of brake material will create a pulsing or throbbing sensation when braking. If you intend to leave the vehicle in a stopped position, place the vehicle in “Park” and release pressure on the brakes.

6. Water from a hose will cool the rotor metal too rapidly and may result in warping.

Do not rapidly cool the brake rotors. The metal in heated rotors will distort during rapid cooling, creating a warp in the plane of an otherwise even rotor. Avoid driving through water that immerses the rotors, if you’ve superheated the rotors as a result of extreme braking. Do not spray your rotors with water to cool them.

7. Worn pads will expose the caliper metal to the rotor surface.

Install new brake pads before the old brake pads reach the end of their service life. Severely worn pads may expose the rotor to metal-to-metal contact. Grinding the rotors with caliper material will etch and wear the rotors unevenly, requiring resurfacing or replacement of the rotor.

8. A metal lathe is used to resurface rotors.

Resurface the rotor when you replace the brake pads. The burnishing process used to ensure both the rotor and pad wear evenly requires new surfaces to facilitate correct burnishing. Pad material is transferred to the rotor during the break-in and burnishing process. If new pad material is applied to the top of old pad material, uneven wear can result. Use a metal lathe to resurface rotors. Many automotive parts stores and machine shops have lathes that can be used to “turn” or resurface rotors for a nominal charge. Call ahead for availability.