CAT® Seal O-Ring 1090078
SKU: 1090078
Brand: CATERPILLAR
Description: O-Rings are used in static sealing and some dynamic applications. Attributes: Cat® O-Rings are made from materials that are matched to the fluids, temperatures and pressures found in Cat engines and machines. The materials resist wear and extrusion, and provide superior resistance to seal compression set. In addition, certain Cat O-Rings are coated with PTFE to minimize seal twisting and cutting during seal installation. Dimensions of our O-Rings are consistently held to tight tolerances to ensure they fit properly into seal grooves with the necessary seal compression. With over 2500 O-Rings in different sizes and materials, Cat O-Rings are your best solution for your Cat and other mobile equipment O-Ring needs. Cat Sealing systems protect more expensive parts from leaks and contamination. Protect your investment with Genuine Cat Seals.
Applications: O-Rings are used in many static and dynamic joints throughout Cat machines and engines.
CAT® SEAL O-RING
- Material: HNBR (78), HNBR - Hydrogenated Nitrile
- Temperature (°C): -40° - 121°
- Seal/O-Ring Type: Standard
- Primary Sealing Material: Rubber
- Cross Section Diameter (in): 0.21
- Cross Section Diameter (mm): 5.33
- Material Description: HNBR provides excellent abrasion and cut resistance. It works well with Air, Engine Oil, Diesel Fuel, Hydraulic Oil and Automatic Transmission Fluid applications. Some formulas may be used with Coolant/Urea.
- Do not use with Biodiesel
- Notes: Dimensions and Material Descriptions provided for reference only. Color may differ from image.
- Dash Size (in): 325
- Not Compatible With: Aromatic and oxygenated gasolines; Automotive and aircraft brake fluids; Chlorinated hydrocarbons; Ethers; Ketones; Phosphate ester fluids
- Inside Diameter (mm): 37
- Compatible With: Abrasion resistant; Diesel fuels; Diester lubricants; Ozone; Petroleum oils, greases; Refrigerant HFC - 134a (Non-Freon); Silicone fluids; Steam; Water base engine coolants
- Temperature (°F): -40° - 275°
- Inside Diameter (in): 1.48
- Coating: None
- Seal Inside Diameter (mm): 37.47
- Automotive air conditioner seals; High temperature flex boot seals; High temperature power steering seals; Higher temperature hydraulic seals; Middle cylinder liner seals
Can't find the part you need? Call us at 801-406-2026 for assistance.

Caterpillar Authorized Dealer
For more than 95 years, Caterpillar has provided innovative products and a world-class dealer network to serve multiple industries.
Back in 1925, Holt Caterpillar Co. and C.L. Best Tractor Co. joined to better meet the needs of customers. They built on each other’s strengths to deliver innovative products and give customers more than just a product. Today, Caterpillar is synonymous with getting the job done.
Over the years, Caterpillar products and services have helped with infrastructure projects that built and powered the modern world. Caterpillar prides itself on the quality of its products and services to the people who stand behind them.
Caterpillar’s Energy and Transportation division is a model for dependability and environmental responsibility. Customers know they can rely on the Caterpillar name and services. The Caterpillar brand uses cutting-edge technology, decades of product expertise, and services offered throughout the product life cycle.