429 Viton O-Ring 75A Durometer 5 in ID 5-1/2 in OD - Durable Seal

In this review the 429 Viton O-ring is examined for practical sealing tasks where chemical and heat resistance matter. The bottom line: this pack of five well-sized, black Viton rings is aimed at technicians, hobbyists, and maintenance crews who need a reliable, heat- and fuel-resistant seal; the single biggest reason to buy is the material performance, since the Viton compound offers broad chemical compatibility and a wide temperature range that handles demanding environments.

Key Features

• Material: Made from Viton fluorocarbon elastomer for strong resistance to fuels, aromatic and aliphatic hydrocarbons, and many common chemicals.
• Temperature range: Usable from -15 degrees F to 400 degrees F, allowing deployment in both cold storage and high-heat systems without rapid degradation.
• Durometer: A 75A shore hardness that balances flexibility and resistance to penetration for long-lasting sealing under compression.
• Shape and fit: Round cross-section designed to form a reliable seal between cylindrical overlapping surfaces in pumps, barrels, and fittings.
• Standards: Sized to meet AS568A dimensions so it fits common replacement needs where that standard is used.

Who It's For

The 429 Viton O-ring is best for professionals and DIYers who work with fuel systems, hydraulic components, or outdoor equipment that sees heat and ozone exposure; it is a practical choice for applications like fuel bottles, suppressor seals, and pump assemblies where chemical resistance and temperature tolerance are required. Its 5 in ID and 5-1/2 in OD make it suitable for larger fittings rather than tiny plumbing or precision instrumentation.

Those who should look elsewhere include users needing compatibility with strong alkalis, ammonia gas, low molecular organic acids, or glycol-based brake fluids, since Viton is vulnerable to those substances. Also, if extreme flexibility at subzero temperatures below the listed range is required, a different elastomer might be better.

Pros & Cons

Pros

• Excellent chemical and fuel resistance for use in contact with many hydrocarbons and silicone oils.
• Wide operating temperature range that holds up under heat and high-vacuum environments.
• Durable 75A hardness that customers report resists penetration and prevents cracking from over-tightening.
• Sold as a pack of five, offering good value for replacements and multiple projects.

Cons

• Not compatible with certain chemicals like ammonia, strong alkalis, glycol-based brake fluids, and super-heated steam, limiting some applications.
• Heavier durometer may be less forgiving in seals that require very soft, low-compression fittings.

Specifications

Our Verdict

The 429 Viton O-ring is a practical, cost-effective choice for users who need a heat- and fuel-resistant seal in mid-to-large sized fittings; its Viton composition and 75A hardness deliver dependable durability and broad chemical compatibility for most fuel and hydrocarbon applications. Buy it if you need reliable replacement rings for pumps, bottles, or outdoor gear, but choose a different compound when exposure to ammonia, strong alkalis, or glycol brake fluids is expected.

Frequently Asked Questions

Are these O-rings suitable for contact with gasoline and diesel?
Yes, Viton is compatible with many fuels and aromatic and aliphatic hydrocarbons, making these rings appropriate for gasoline and diesel exposures.

Will the 75A hardness work for sealing a metal-to-metal threaded joint?
75A provides a firm seal and good resistance to penetration, but if a very soft compressible gasket is required these rings may be stiffer than alternatives.

Do they fit standard AS568 sizes?
The rings are made to the dimensions noted and conform to AS568A sizing conventions so they can replace seals specified to that standard.