4426128 Original Excavator Spare Parts Circular Plate for ZX200 

Part number 4426128 is a specialized part number for the structural connection plate of Hitachi's original excavator. This component is clearly marked as "PLATE" in the parts list and is a key structural component at the connection between the excavator boom (boom) and the chassis or turntable. It is usually used as a mounting plate, pad, or baffle for the boom foot pin (Frame Boom Foot Pin), which plays a role in positioning, supporting, and dispersing loads. As an original standard component, it is mainly suitable for hydraulic excavators such as Hitachi ZX350-5, and may also be applicable to other similar tonnage models in the ZX series (such as ZX330, ZX360, etc.).

This original connecting plate belongs to high-strength structural load-bearing components. Its core function is to serve as an important component of the hinge point between the boom and the lower frame or rotating platform. By cooperating with other components such as pins and bolts, it reliably transmits the huge working load (excavation force, self weight, impact load) of the boom to the chassis, ensuring the structural rigidity and stability of the entire working device. As an original component, it is usually made of high-quality alloy structural steel (such as Q345B or higher strength grade) through precision cutting, drilling, heat treatment, and rust prevention treatment, with extremely high tensile strength, fatigue resistance, and excellent dimensional stability. Its precise thickness, pin hole diameter, bolt hole spacing, and possible positioning stop design ensure perfect fit with adjacent components.

The maintenance core of this structural connecting plate lies in regularly checking its fastening status, structural integrity, and preventive replacement. When replacing, special tools should be used to disassemble and strictly follow the sequence and torque values specified in the maintenance manual. Use a calibrated torque wrench to tighten all connecting bolts in stages and cross tighten them. After installation, it is recommended to conduct necessary dimensional checks and test the machine to observe for any abnormal noise or looseness. As it is a critical structural safety component, any repair or replacement operation must be carried out by qualified professional technicians.