It doesn't sound like this was your problem, but here's some useful info....
Whenever you install wheels, always ALWAYS torque the wheel nuts to the PROPER torque and in the correct sequence.
Most tire places don't do this. They have a guy that stands there with an impact gun, and blasts the nuts on there at 100lbft without paying any attention to the manufacturer's recommended setting.
That can warp your brake rotors (warped rotors manifest themselves as a pulsating feeling in the pedal whenever the brakes are applied). Too much torque on the wheel nuts, and especially uneven torque (ie, one at 100lbft, one at 80, onr at 90, etc.) will create uneven pressure on different parts of the rotor and can cause them to warp. Especially if the rotors aren't top-quality to begin with. (we all know how fantastic GM's brakes are....)
Invest in a good torque wrench and always torque the bolts in the correct sequence (zig-zag for 4-bolt wheels, star-pattern for 5-bolts) and to the correct torque, and your brakes will thank you...
