3112376 Original Excavator Seal Ring for ZW220

Part number 3112376 is the original sealing ring specially designed by Hitachi for the ZW220 wheel excavator. Its universal model is this part number, mainly used for static sealing of key parts such as valve block joint surfaces, sensor interfaces, or pipe joints in the hydraulic system of this model. As an original precision seal, its inner diameter, outer diameter, thickness (cross-sectional height), and material hardness are all perfectly matched with the corresponding sealing groove (usually rectangular groove) on the equipment. It is strictly prohibited to use universal O-rings or substitutes with mismatched dimensions to avoid uneven pressure on the joint surface, seal failure, oil leakage, or abnormal system pressure.

This product is a sealing ring, which is a standard black circular ring with a precise rectangular cross-section and clear four corners. Its material is usually nitrile rubber (NBR) or hydrogenated nitrile rubber (HNBR) with excellent oil resistance, pressure resistance, and compression permanent deformation resistance. This rectangular cross-section design provides a larger contact area and more uniform sealing pressure when installed in a flat groove, making it particularly suitable for medium to high pressure static sealing applications. Its working temperature range is usually -30 ℃ to+120 ℃, and it can withstand long-term immersion in hydraulic oil and system pressure shock. The smooth and burr free surface of the sealing ring in the picture is a reflection of its excellent factory craftsmanship.

Installation specifications (key in cleaning and alignment): 1 Cleaning: Before installation, the sealing ring itself, installation groove, and all mating metal surfaces must be thoroughly cleaned with a lint free cloth and specialized cleaning agent to ensure that there are no particles, scratches, or residual old sealing materials. 2. Lubrication: During installation, apply a very thin layer of compatible grease or clean hydraulic oil on the surface of the sealing ring (3112376). 3. Smooth insertion: Use your hand to place the sealing ring flat and without distortion at the bottom of the groove, ensuring that it is fully seated and there is no lifting or extrusion around it. 4. Alignment tightening: When installing the upper cover or fitting parts, align the positioning pin, smoothly lower it, and then use a torque wrench to cross tighten the bolts in the prescribed order and torque (refer to the maintenance manual) in stages to ensure that the joint surface is uniformly compressed