What must be adjusted for rear steering system operations?

For rear steering system operations, it is essential to adjust the hydraulic pressure settings because rear steering systems often rely on hydraulic mechanisms to enable steering control. The hydraulic pressure must be calibrated properly to ensure that the steering response is both accurate and responsive. If the hydraulic pressure is too low, it could result in sluggish or imprecise steering, making the vehicle harder to maneuver, especially in tight spaces. Conversely, if the pressure is too high, it could lead to overly sensitive steering which might compromise safety and control.

In the context of the other options, while valve settings for electrical systems and control switches for forward and reverse functions are important in various operational contexts, they do not directly pertain to the adjustments needed specifically for the rear steering system's hydraulic functionality. Isolation of unnecessary circuits is more about ensuring operational efficiency and safety but does not directly influence the steering performance itself. Therefore, focusing on hydraulic pressure settings is crucial for effective and safe steering operations in rear steering systems.