Methodiclly check for the culprits.
Steering play. There's often a little play in the box when the car isn't moving and wheels are straight. That said..
First - check the wheel bearings aren't loose. If there is in/out movement when you hold the wheel top and bottom (12 and 6),tighten to specs.
Second - With one wheel on the ground move the wheel off the ground as the steering wheel would (hands at 3 and 9 oclock). Watch each link and joint in the steering linkage until you see the movement.
Then do it from the other side. Get a helper if you need. I prefer to do it myself even though it was awkward because I can feel the movement if there is any and match it with what I'm seeing. Even though there's no steering lock, you'll see the pitman arm rock if there's wear or slop in the steering gear's bearings.
Finding nothing in the front, check the rear springs at both the hangers and shackels. Bet you find something in the front though.
One more tip. Look at each tire for clues in the wear patterns.
