Ford Repair: brakes, mustang v6, ball joints

Question
Hey Mark i have 2003 Ford Mustang V6 every time i apply the brakes it pulls to the left, i've checked the front brakes and they have about 45% left and also rotated the tires but still no luck

Answer
several things it could be-from suspension parts like ball joints
to sticking caliper-bad brake hose-i doubt tires are related to this since rotating did not help- i would definitely have brakes checked it may be hard to determine what it is but caliper and/or hose are most common.