4179156 Excavator Pump Regulator Spool for Hitachi ZX200

Part number 4179156 is a genuine pump control slide valve produced by Hitachi Construction Machinery in Japan. The support chain (walking) system specifically designed for crawler excavators, on the ZX200, is the core precision valve core that controls displacement, achieves continuously variable speed and steering in the walking motor or main pump variable mechanism. Mainly suitable for Hitachi ZX200 series (such as ZX200-3, ZX200-5G) and other tracked medium-sized excavators. As the original "control center", its diameter, ring groove spacing, shoulder width, and valve body hole are precisely matched and researched

This product is a cylindrical slide valve made of precision ground alloy steel. The valve body is silver gray in color and has multiple precision annular grooves machined on the surface. The grooves are shoulder shaped to control the opening and closing of the oil circuit. The flange edge at one end is usually used for installation positioning or connection with drive mechanisms such as proportional electromagnets and pilot pistons. The core working principle is to make small axial movements in the inner hole of the valve body, and precisely control the direction, flow rate, and pressure of high-pressure oil by changing the corresponding relationship between each ring groove and the oil port on the valve body, thereby achieving stepless proportional adjustment of walking speed, torque, or pump displacement.

Fault diagnosis: If there is unilateral walking weakness, deviation, inability to change speed, or system pressure fluctuations, after ruling out the pilot pressure, it is suspected that the wear of the slide valve is causing internal leakage or the valve core is stuck. Timing of replacement: Once it is confirmed that the slide valve is worn out beyond tolerance, pulled or stuck and cannot be repaired, it must be replaced, and it is recommended to check or replace the valve body synchronously. Attention: Before disassembly, be sure to release all system pressure; When storing, it should be soaked in clean hydraulic oil and sealed to prevent rust and collision.