... YC4FA90N-30 YC4FA100N-30,XINCHAI..HYDRAULIC SYSTEM: MAIN PUMP, PILOT PUMP AND VALVE, WORKING PUMP, CONTROL VALVESTEERING SYSTEM: STEERING UNIT, STEERING PUMP AXLE ... L=638, center slewing joint, center slewing joint, stay leg control system, cover plate assy, hydraulic oil case, hydraulic oil case support ...