4703557 Original Excavator Bolt for ZX330-3

The original bolt part number 4703557 is a key high-strength fastener specifically designed for the installation of support wheels on Hitachi ZX330-3 series large excavators. It is mainly compatible with ZX330-3, ZX330-3G, ZX330LC-3 and other ZX330-3 series models, and may also be compatible with Hitachi large excavators of similar tonnage such as ZX360LC. This bolt is used to firmly fix the support wheel assembly on the track frame, and withstand the huge impact and vibration during excavator operation. When placing an order, the complete model and serial number of the equipment must be provided to ensure that its diameter, length, and thread specifications are exactly the same as the original bolts.

This product belongs to high-strength internal hexagonal cylindrical head bolts, usually made of alloy steel (such as SCM435), and has undergone quenching and tempering heat treatment, with a strength grade of up to 10.9 or 12.9. The surface is treated with Dacromet or phosphating rust prevention. According to official technical information from Hitachi, the standard torque for bolts of this specification used for ZX330-3 support wheels is 670 N · m (approximately 68 kgf · m), and a 30mm socket wrench is required for tightening. As an original component, its thread accuracy, tensile strength, and anti loosening performance are strictly matched with the overall design requirements, ensuring long-term reliability under harsh working conditions and avoiding serious safety hazards such as bolt breakage and support wheel detachment caused by insufficient strength of auxiliary components.

Before installation, it is necessary to clean the threaded holes and confirm that the threads are not damaged; When tightening, a torque wrench must be used to tighten in diagonal order to the specified torque. Regular inspection: It is recommended to check the tightening status of all supporting wheel bolts every 250 working hours. If there is any looseness, it should be immediately re tightened according to the specifications. Preventive maintenance: Medium strength thread locking agent can be applied to the bolt thread to enhance the anti loosening effect; If bolt thread damage, head wear, or tensile deformation is found, it must be replaced immediately. Replacement suggestion: The bolt of the supporting wheel is a critical safety component, and the use of non original or unknown strength substitutes is strictly prohibited; It is recommended to replace all bolts in the same group with new ones and use original parts to ensure consistent pre tightening force and anti loosening performance.