Most likely cause is one of the steering drag links is bent, or the wheel spindle is bent. Since they started using two drag links, instead of a single drag link and then a tie rod, this has been a major pain as far as steering goes. Doesn't take much sometimes to bend on of the links, and then the steering is off, and will not steer correctly.
I Once installed a new link on a MTD years ago, and then turned the wheels to the right, and pretzelled the link. Cause there was rust in the axle where the steering spindle was installed, causing excessive resistance when turning.
