Caterpillar 5J-7012 Ring Expander And Seal

Caterpillar 5J-7012 Ring Expander and Seal is an OEM Cat component designed for hydraulic cylinder piston seal assemblies, built to maintain effective oil separation between cylinder chambers. The part is cataloged as 5J-7012 and features a 74.7 mm inner diameter expander ring, a dimension that defines its fit within CAT cylinder configurations. This ring works in concert with piston seals to seat the groove properly and prevent cross-leakage, supporting reliable cylinder performance during heavy equipment operation. This 5J-7012 item is used in Cat hydraulic systems that require a dedicated expander ring as part of service and rebuild workflows, and it is listed in Cat Parts Store and distributor catalogs as the standard 74.7 mm inner-diameter expander ring. Engineers and technicians typically source it for cylinder maintenance on CAT machinery across construction, mining, and other industries where Caterpillar equipment is in service, ensuring compatibility with Cat seal assemblies and related components. As an official Cat part, the 5J-7012 designation identifies a precise fit within the Cat seals-and-expansion-ring family, enabling technicians to restore seal integrity and cylinder efficiency when servicing hydraulic cylinders that call for a ring expander and seal arrangement.