Brakes are, by far, the largest volume repair in most independent repair shops today. They can be a very profitable service when performed correctly. Depending on how the vehicle is driven, proper brakes repair should last anywhere from 65 000 to 100 000 km, except of course, mail deliveryvehicles, etc.
Pads and brake rotors are the foundation of any ABS, stability, or traction control system. Without the right friction levels or rotor surface, these complex systems will not operate properly. This is why extra attention should be paid to any late-model vehicle when performing basic brake repairs.
As vehicle weight became a great concern due to increased fuel mileage, manufacturers began designing brake components lighter and with the composite rotors cast with two alloys. These lighter components on today’s modern vehicles tend not to absorb vibrations as well. These new designs are even more prone to stacked tolerances in the knuckle-to-bearing and hub-to-rotor assemblies. Rust and corrosion have increased the chances of lateral run-out and thickness variations as well.
Lateral brake run-out means the rotor wobbles from side to side when spinning. Lateral run-out will cause the rotor to contact the brake pads, knocking them back as the high spot of the run-out contacts the pads, allowing more pedal travel before the pad’s surface makes contact with the rotor. Rotor run-out will lead to thickness variations, inevitably leading to brake pulsations.
Pulsations can take some time for the vehicle occupants to feel and they may continue to drive the vehicle for months after, increasing the pulsation until it is unbearable. The customer now returns with a brake pulsation concern or worse — they don’t return to your shop at all. They may have the vehicle repaired elsewhere, not giving you the opportunity to correct the concern. So, eliminating any chance of a pulsation or noise concern the first time will increase customer satisfaction.
Full source credit: https://www.knowyourparts.com/technical-resources/brakes-and-brake-components/brake-rotor-service-tips/
