4375722 Excavator Load Cylinder Piston for Hitachi ZX200

Part number 4375722 is the original hydraulic cylinder piston specially designed by Hitachi for the ZX200 series hydraulic excavator. This component is the core motion and pressure conversion component inside the hydraulic cylinder of the working device (such as boom, arm, or bucket). Mainly used for ZX200-3, ZX200-5G and other platform models. As an original precision core motion pair, its outer diameter, length, sealing groove size, and connection method with the piston rod are all precisely matched with the corresponding model of oil cylinder barrel

This product is a precision machined oil cylinder piston made of high-strength alloy steel. The main body is a black cylindrical shape, and the surface has undergone special hardening treatment (such as chrome plating or nitriding), which has extremely high wear resistance and corrosion resistance. There are several uniform annular grooves machined on the outer circumference of the piston, which are precision sealing grooves used for installing composite seals, wear-resistant rings, and guide rings. The center or one end usually has a precision machined threaded hole or protrusion, used for a secure connection with the piston rod. Its core function is to perform reciprocating linear motion inside the cylinder under the pressure of hydraulic oil, thereby converting hydraulic energy into mechanical energy. It is the "source of power" that drives the excavator boom, forearm, and bucket to make various powerful movements.

Installation and maintenance: The replacement of this piston falls within the scope of hydraulic cylinder overhaul. 1. Disassembly and inspection: Before maintenance, the system pressure must be completely released. After disassembling the oil cylinder, the piston and cylinder must be thoroughly cleaned, and the surface of the piston must be checked for any scratches, rust, or broken edges of the sealing groove. At the same time, the outer diameter wear should be measured to see if it exceeds the tolerance. 2. Seal replacement: When installing a new piston (4375722), all seals must be replaced as a set and clean hydraulic oil must be applied to the seals. 3. Alignment installation: After connecting the piston to the piston rod with the specified torque, smoothly and accurately install it into the cylinder to prevent scratching the seals or cylinder walls. 4. Testing: After the assembly of the oil cylinder assembly is completed, a pressure test must be conducted to ensure that there is no internal or external leakage.