Product Overview This hydraulic main pump, available under part numbers 190-8199, 251-8034, and 20R-7235, is the primary hydraulic power unit engineered specifically for the hydraulic system of M318 and M322D wheel excavators. It delivers high-pressure hydraulic oil to drive the boom, arm, bucket, travel, and swing assemblies. Built with a variable piston structure, the pump features precise flow control, wear-resistant alloy materials, and precision machining. It is designed