I just replaced the front rotors on my car, and.

I just replaced the front rotors on my car, and replaced the break pads. A few months back, I started getting a shimmer through the front seats and the steering wheel whenever I hit the breaks. I then had the rotors cut, and now the shimmer is worse whenever I hit the breaks. I checked tie rods, front suspension for play in the front wheels, but there is none. What else could it be?