Next, jack up the car. You suspected a cracked control arm so take a look. Check the ball joint on the control arm to see if it is worn. Check the control arm bushings also to see if they are worn. No? Good. Yes? Bad.
Grasp the tire at 12 and 6 o'clock and push/pull to see if there is any movement. Any movement at 3 and 9 o'clock? There shouldn't be any movement if steering/suspension parts are okay.
Check your sway bar bushings. Worn?
Replacing the steering/suspension is pretty easy...except for the control arm stuff.