Did you have the brake rotors machined? If so, they should have cleaned off the rust buildup on the back where it contacts the hub. There are holes in the hub and water gets up there and causes round circles of rust to form. If that is not cleaned off, the rotor will not sit squarely on the brake lathe and a warp will be machined into it.
If you removed the rotor and just reinstalled it, turning it one quarter or one fifth of a turn will do the same thing because those raised rust spots will no longer line up with the holes that let them develop. Also look for other rust or scale the fell between the rotor and hub and the rotor and wheel. You can identify that by supporting the front end on jack stands, running it in gear, and watching the wheel to see if it's moving left and right as viewed from in front of the car.
Did you use a torque wrench when tightening the lug nuts? Most shop owners will fire an employee who is caught multiple times not doing so. Over-tightening will damage the friction surfaces where the lug nuts contact the wheel, and can peal the threads on the nuts and studs. You won't notice that until the next time you try to get the nuts off. That's when customers unfairly blame the mechanic. It was the previous guy who caused the damage.
Under-tightening can allow the wheel to slide under the lug nuts. That will cause wear to the precise mating friction surfaces and lead to the wheel coming loose. Most commonly, failure to use a torque wrench results in uneven clamping forces from all of the lug nuts. That will result in a warped rotor and brake pedal pulsation and possibly steering wheel shimmy, but that may not show up for weeks or months.
Did you put some high-temperature brake grease between the hub and the rotor's center hole? If you put it together dry, the rotor can resist the tension from the lug nuts and may not sit squarely on the hub.
You will also see there is rust formed on the back of the rotor starting right at the outer edge of the hub surface. That is supposed to get scraped off before machining. Even when it does, that is where some of it can break off and get trapped between the rotor and hub. That will make the rotor and the wheel wobble a little.
Wednesday, October 24th, 2012 AT 10:14 AM