This steering column O-ring seals the joint between the steering column and its housing in the host tractor. It prevents hydraulic fluid or lubricant from leaking past the rotating shaft, maintaining pressure and cleanliness inside the steering system. A degraded O-ring allows fluid seepage, which can lead to a loss of steering assist and contamination of the surrounding area. The original manufacturer specifies the material and cross-section to match the groove geometry of the steering column housing, ensuring a consistent seal under operating pressure. Replace the O-ring whenever the steering column is disassembled.