This hydraulic power steering gear assembly (also known as steering box) is a core component of FAW Jiefang J6 heavy truck steering system. It converts the rotary motion of the steering wheel into swing movement of the pitman arm, and provides hydraulic power assistance to reduce the driver’s steering effort. Adopting recirculating ball hydraulic power-assisted structure and ductile iron housing, it features high rigidity and strong impact resistance under heavy-load and long-haul driving conditions. The internal precision valve assembly ensures fast and stable response for steering operation. Every steering gear undergoes pressure cycle test, leakage inspection and performance calibration before delivery. It solves common faults such as heavy steering, unstable return-to-center, oil leakage and steering jitter, serving as a key replacement spare part for heavy truck steering system overhaul.