Porsche 928 Resurface Rotors Cost

Most modern passenger vehicles use disc brake systems on all four wheels. Brake rotors are the final part of the braking system, and use friction created by the brake pads to slow or stop the vehicle. When the brake pads are changed, the rotors must be replaced, but if sufficient thickness remains, the rotors may be resurfaced to a like-new condition.

As the term “disc brake” implies, the brake rotor is shaped like a disc. This disc rotates with the vehicle's wheel until the brake pads squeeze the rotor from both sides to create braking force. The brake rotor transmits this braking force directly to the wheels, and causes the vehicle to slow down.

Brake rotors are mainly maintenance free, but when they have been subjected to abnormally hard use, the heat they absorb can cause the metal to turn blue, and cracking to occur. When this occurs, customers often specify they have lost braking power, or the vehicle's brakes are making noise. There may be no symptoms at all related to replacing or resurfacing the brake rotors, since it is recommended to resurface or change brake rotors when performing a standard disc brake service.

It is not safe to operate any vehicle with any braking problem. If there exists any sign that the brakes are not performing as originally intended, the vehicle should immediately be placed out of service, and repaired. If the rotors are being replaced as part of routine maintenance, with no symptoms noticed, the vehicle can safely be driven to a repair shop.

Brake rotors are typically replaced or resurfaced as part of a standard brake service, so the average serviceable lifespan depends on driving style, and operating conditions. The manufacturer recommended maintenance schedule for each vehicle may be different, and the owner's’ manual will contain this information.

Trained technicians have replaced or resurfaced hundreds, if not thousands, of brake rotors through their careers, and training time. The signs they look for when disc brakes are suspected of failure are deep grooves, stress fractures, and a blue color indicating the brake rotor has exceeded the allowable heat range. If any of these conditions exist, the technician will recommend replacement, or resurfacing if appropriate.

To replace a brake rotor, the wheel, brake caliper, and a retaining screw must be removed from the vehicle. If the rotors are being replaced, the replacement rotor is installed by sliding onto the hub and bearing assembly, and cleaned before installing the brake caliper and brake pads. If the brake rotor is eligible for resurfacing, according to material type and thickness, the rotor will be installed on large piece of industrial equipment known as a brake lathe. The brake lathe resurfaces the rotor by spinning the rotor while a stationary metal cutting head is applied to the surface, and scraped across. Once the cutting head has made several “passes” across the sides of the rotor, it will be cleaned, and measured to ensure adequate thickness has been retained. If the thickness is too low, the rotor must be replaced, otherwise, the rotor will be installed by sliding onto the wheel studs, and a retaining screw may be used to position the rotor against the hub and bearing assembly. Afterwards, the brake caliper and pads will be installed, and the brake system will be bled and flushed to eliminate air and contaminated brake fluid. Wheel nuts, also called lug nuts, must be tightened to manufacturer's’ specification to complete the repair.

When replacing a brake rotor, it is important to replace the corresponding rotor on the other side of the vehicle. This will ensure the braking power is even and predictable. Brake pads show wear patterns after many times of grinding into the old brake rotor, and must be replaced to avoid brake noise, uneven braking pressure, and unpredictable braking performance.

Some brake rotors are mounted onto the wheel bearings, and those bearings should be repacked with grease or replaced when the rotor is removed. Any grease or automotive fluid, besides water, on the brake rotor will instantly contaminate the brake pad, necessitating replacement of the pads. To avoid this, the rotors should be cleaned with brake parts cleaner prior to installation of the brake pads and caliper. Some modern rotors are manufactured using composite materials which may be metallic, semi-metallic, ceramic, Kevlar, or carbon fiber. Metallic brake rotors are the only type eligible for resurfacing, and all others must be replaced. Semi-metallic brake rotors may be an exception to this rule, depending on manufacturer specification. Rotors that cannot be machined are typically more expensive, and offer much higher braking performance. If they are re-used, uneven pressure from new, flat brake pads may cause cracking, loss of braking power, and unpredictable braking performance, which may lead to a collision. These rotors must be changed when a brake service is done, or the vehicle will not be considered safe to drive.

Specialized heavy equipment is necessary to resurface a brake rotor. There are several products available to consumers to resurface rotors at home, on the vehicle, but these products will not produce the smooth, flat finish necessary for proper mating to a new, flat brake pad. If a resurfacing service is not available, the rotor should be replaced with a new part.