pulsating in brake pedal

The pistons in the calipers could be hanging up on return after brake applications.Also a good idea at this time is to check the brake flex hoses at both the front wheels.One could be restricted a bit which may cause your steering to feel funny pulling to one side while braking and also a feeling like a tire has a not on it,like a unusual brakeing drag or failure to release.This will cause the rotor or rotors to get hot and warp.The flex hoses can get restricted at the mounting bracket,that wraps around the hose assembly!

Does this car have anti lock brakes?

A pulsating brake pedal is usually caused by warped brake rotors. If this pulsating was not there before the brake work and started right after the pads and shoes were replaced then the rotors are faulty or more likely, there is rust on the hub mounting surface beneath the rotor that causes the rotor to warp when the lug nuts are tightened. Some of this could also be caused by the wrong torque value and sequence. 100 lb ft is the correct torque and a star pattern is the correct torque sequence.