Seal Ring / Washer

What Are Seal Rings and Washers?

Seal rings and washers are deceptively simple components that perform one of the most critical jobs in any mechanical system: keeping fluids exactly where they belong. Seal rings and washers are flat or ring-shaped fastener components placed between mating surfaces to create a fluid-tight or gas-tight barrier. Whether installed around an oil drain plug, a hydraulic fitting, a fuel line connection, or a brake line junction, these small parts prevent leaks that can cause costly damage, safety hazards, and performance failures.

Why Seal Rings and Washers Matter

It's easy to underestimate a part measured in millimeters — but a failed seal ring can mean the difference between a dry engine bay and a puddle of oil on your garage floor. Sealing washers serve a dual purpose in fastener assemblies: they create a reliable fluid barrier at the joint and help maintain clamping force, reducing the risk of vibration-induced loosening over time. In automotive engines, brake systems, fuel lines, and transmission assemblies, the integrity of every connection depends on a properly seated, correctly specified seal ring or washer.

Different applications call for different designs. Copper crush washers are commonly found in high-pressure hydraulic and brake line fittings, where they deform under torque to fill microscopic surface irregularities. Bonded sealing washers — sometimes called Dowty washers — combine a metal carrier with a rubber sealing element, making them a go-to choice for engine oil drain plugs and hydraulic fittings. Rubber and elastomeric washers in materials like EPDM, NBR (nitrile), neoprene, and PTFE each offer distinct resistance profiles against oils, fuels, chemicals, and temperature extremes, allowing engineers and technicians to match the seal material precisely to the application environment.

Choosing the Right Seal Ring or Washer

When selecting a seal ring or washer, a few key factors come into play:

• Material compatibility: NBR (nitrile) excels in oil and fuel environments; EPDM handles water and weather exposure well; PTFE/Teflon stands up to aggressive chemicals and high temperatures.
• Pressure rating: Crush-style and bonded washers are better suited for high-pressure connections, while softer rubber washers work well in low-pressure or static sealing situations.
• Dimensional fit: Inner diameter (ID), outer diameter (OD), and thickness must match both the fastener and the seating surface to ensure a proper, leak-free seal.
• OEM vs. aftermarket fit: For restoration and repair work, matching the original manufacturer's specifications ensures reliable, long-term performance.

Top Brands in Seal Rings & Washers

When it comes to dependable sealing components, Fairchild stands out as a trusted name in the industry. Fairchild Industries was founded in 1961 and has built a reputation over six decades as a leading designer and manufacturer of rubber and plastic sealing solutions for the automotive, marine, agriculture, and construction sectors. Their ISO-certified manufacturing facility in Illinois uses precision tooling and advanced engineering processes — including 3D measurement systems — to ensure consistent, accurate fit across thousands of part numbers. For technicians tackling everything from routine maintenance to full vehicle restorations, Fairchild's sealing components deliver OE-quality fit and long-term durability.