Caterpillar 2K-2961 Ring

Caterpillar 2K-2961 is a Cat® rubber backup ring engineered for hydraulic cylinder sealing on Cat equipment, designed to prevent O-ring extrusion under pressure and maintain a dependable seal in moderate-temperature hydraulic service. It has an inside diameter of 132.73 mm (5.23 in), a cross-section width of 1.1 mm (0.04 in), and a cross-section height of 2.9 mm (0.11 in); the material is urethane rubber with variations including nitrile/NBR/HNBR/XNBR per Cat specifications, and it should not be used with water-soluble fluids. Cat lists this part as a factory-fit backup ring compatible with a broad range of equipment, spanning wheel tractors, wheel loaders, backhoe loaders, motor graders, track-type tractors, and other Cat machines, reflecting the brand’s seal engineering across multiple model families. Notes from Cat’s product pages indicate dimensions and material descriptions are provided for reference, and color may differ from the image.