How far did someone go with the inspection? Did they pull the rotors off? One common thing to look for is raised spots of rust on the back of the rotor mounting surfaces. Those form where water gets in through the wheel bearing access holes. That rust needs to be scraped off before the rotors are mounted on the brake lathe to be machined. If they are not removed the rotor could wobble on the lathe and a warp will be machined into the rotor. It's also possible for those spots to get stuck between the rotor and hub when the rotor is reinstalled in a different orientation. That will also make it wobble on the car. You'd find that by measuring "lateral runout" with a dial indicator. The noise you described could be due to the wheel and tire wobbling and the tire is scrubbing back and forth on the road, or it could be due to the caliper sliding back and forth when no brake grease was used on the mounting points.
If the rotors were not machined there is going to be a ridge of rust on the outer edge and the inner edge, and the new linings could be rubbing on them. That will wear away over time. That's not easy to spot during a visual inspection.
Wednesday, June 19th, 2013 AT 10:57 PM