Block a rear wheel. Raise the front wheels clear of the ground. Turn the steering wheel completely one way and grasp the steering rack bellows boot until you can feel the tie rod socket and steering rack. Have someone shake the steering wheel back and forth enough to cause the front wheels to shake. The rack and tie socket should move completely in unison. If the rack moves before the tie socket/wheel, the inner tie socket is bad and should be replaced. Do this on both sides. Next, squeeze the outer tie rod ends firmly. You should not be able to induce any up and down movement of the tie rod in relation to the steering knuckle. If you do, the outer tie rod end is bad.
Either of these parts can cause the problems you mention.
Sunday, November 27th, 2011 AT 3:20 AM