3112395 Original Loader D-type Oil Seal Ring for ZW220

The Hitachi original loader D-type oil seal ring (part number: 3112395) is a key component used for sealing hydraulic cylinder piston rods. Its D-type cross-sectional structure can effectively prevent seal extrusion under high pressure. As an original factory seal, this component is mainly suitable for various working cylinders of Hitachi ZW series wheel loaders (such as boom cylinders, bucket cylinders, steering cylinders, etc.), which may involve medium and large machine models such as ZW140, ZW180, ZW220, ZW250, ZW310, ZW330, ZW550, etc.

This D-type oil seal ring is a unidirectional dynamic seal designed to withstand high pressure and dynamic reciprocating motion. Its "D" shaped cross-section allows it to tightly adhere to the bottom surface of the groove on the back (flat side) after installation, forming a firm support and effectively preventing the sealing lip from being squeezed into the small gaps between metal components under high system pressure (such as withstanding pressures up to 40MPa or higher), thereby avoiding seal failure and component damage. As an original component, it is usually made of high-performance polyurethane (PU) or composite materials, which have excellent wear resistance, tear resistance, high elasticity, as well as good resistance to hydraulic oil and aging performance.

The maintenance core of this oil seal lies in preventive replacement, standardized installation, and condition monitoring. As it is a critical dynamic seal, it is not recommended to wait until there is a leakage before replacing it. Instead, it should be checked or replaced in conjunction with oil cylinder overhaul or regular maintenance (such as every 3000-5000 hours of operation). Before installation, it is necessary to thoroughly clean the oil cylinder groove and piston rod to ensure that there are no metal debris or dust. Special installation tools or guide sleeves must be used during installation, and clean hydraulic oil should be applied to the oil seal lip and piston rod surface. It is strictly prohibited to use sharp tools such as screwdrivers to pry and install directly, in order to avoid cutting the sealing lip