If the problem started right after the brake service, it should have been noticed during the test drive. It is possible to machine the rotors and accidentally machine a warp onto them which could be what you're feeling. New rotors often warp right after they've been installed, ... Well, ... Within a few weeks. A simple machining will take care of that. Reputable shops will typically do that at no charge if they did the previous brake work.
The system should be inspected by the same shop that did the previous work. Someone will test drive it after you explain what it's doing. Very often they can tell what is wrong just be how it feels
Wednesday, May 11th, 2011 AT 9:48 PM