What could be the cause of steering binding in a medium duty truck after U-joint replacement?

Steering binding in a medium duty truck following U-joint replacement can often be attributed to incorrect U-joint phasing. U-joint phasing refers to the alignment of the U-joints within the drive shaft; if they are not properly aligned, it can create angular misalignment. This misalignment results in excessive friction and binding during steering maneuvers, especially when the steering is turned to its extremes. Proper U-joint phasing ensures that the angles of the U-joints match correctly, allowing for smooth operation and no binding.

The other options relate to different aspects of steering performance but do not directly address the issue of steering binding following a U-joint replacement. Improper steering geometry might affect handling but wouldn't typically result from U-joint work. Worn steering components could be a general cause of steering issues, but this would likely present symptoms independent of recent U-joint replacement. Improved turning radius is generally a desirable outcome and not related to steering binding, as it suggests enhanced maneuverability rather than the presence of a problem.