If a steering gear binds when turning left, what is the most likely cause?

When a steering gear binds while turning left, the most likely cause is high worm bearing preload. The worm gear mechanism in a steering assembly relies on precise spacing and tension to function smoothly. If the preload on the worm bearings is too high, it can create excessive friction, leading to a binding sensation when the driver attempts to turn the steering wheel. This binding can manifest more prominently during one direction of turn, such as left, due to the way the internal components align under load.

High preload forces the components closer together, which diminishes the clearance necessary for fluid movement and ease of operation. As a result, the steering gear resists movement, and the driver's effort to turn the steering wheel feels artificially difficult or 'binds' as it reaches certain angles.

Other options, while they might cause issues within a steering system, are less likely to lead specifically to binding in one direction. For instance, incorrect lash adjustment could lead to general sloppiness or play rather than a specific binding in turning. Poor lubrication could affect the entire steering range but typically would not singularly cause binding in only one direction and can cause different symptoms like stiffness overall. Faulty torque specifications would generally affect fastening integrity rather than the normal operation of the steering mechanics like binding