when i drive my 2001 focus at about 50 mph when i press on the brakes it makes a grinding sound and shakes really bad. when i jacked up one side of the car and move the rotor side to side it has a little bit of movement in the rack and pinion. the brakes and rotors on both sides are fine , need a lot of help

 

Your rack and pinion should not make any grinding sound when you apply the brakes. You may have rack and pinion problems due to the shacking, it more likely be tie rod ends. Not sure what the grindig is