388 Viton O-Ring 75A Durometer, 19 in ID - Durable Chemical Seal

Our review of the 388 Viton O-ring finds it best suited for technicians, hobbyists, and maintenance crews who need a reliable replacement seal for fuel, hydraulic, or high-heat equipment. The bottom line: this pack of ten O-rings delivers consistent fit and chemical resistance because it uses genuine Viton fluorocarbon elastomer at a mid-range 75A hardness, making it a practical choice when heat, fuels, or solvents are present and a sturdy, repeatable seal is required.

Key Features

• Material: Made from Viton fluorocarbon elastomer for broad resistance to fuels and many industrial solvents so the rings last longer in harsh environments.
• Temperature range: Rated from -15 degrees F to 400 degrees F, allowing use across automotive, plumbing, and light aerospace temperature extremes.
• Durometer: 75A hardness offers a balance of flexibility and resistance to penetration, helping maintain a reliable seal under compression.
• Geometry: Round cross-section designed to seal between overlapping cylindrical surfaces, which aids compatibility with common valve and bottle fittings.
• Standards: Manufactured to meet Aerospace Standard AS568A sizes, providing predictable dimensions for replacement and repair.
• Pack size: Sold in a pack of ten, giving spare parts on hand for repeated maintenance tasks or multiple service points.

Who It's For

This product fits people who regularly service systems exposed to fuels, aromatic and aliphatic hydrocarbons, or silicone oils and need a robust seal that tolerates high temperature and vacuum conditions. It is particularly useful for repairs on fuel bottles, barrel seals, switchback components, and other cylindrical fittings where a precise O-ring dimension is required.

Those who should look elsewhere include users whose systems are exposed primarily to alkalis, ammonia gas, low molecular organic acids, amines, glycol-based brake fluids, or super-heated steam, since Viton is known to be vulnerable to those substances and an alternative elastomer would be safer.

Pros & Cons

Pros

• Excellent heat and chemical resistance makes it dependable for fuel and solvent exposure.
• Customers report reliable fit and leak resistance for items like fuel bottles and barrel seals.
• Pack of ten provides value and spare parts for ongoing maintenance.
• 75A durometer balances durability with enough flexibility for many sealing applications.

Cons

• Not suitable for environments dominated by ammonia, strong alkalis, or glycol-based brake fluids.
• Hardness and material choice may be overkill for light domestic plumbing where softer compounds perform better.

Specifications

Our Verdict

The 388 Viton O-ring is a practical, cost-effective choice for professionals and informed hobbyists who need a durable seal for fuel, chemical, or high-temperature applications. Its Viton construction and 75A hardness deliver dependable leak resistance and longevity for the right environments, making the ten-pack a good value for routine maintenance and repairs.

Frequently Asked Questions

Can these O-rings handle gasoline and diesel?
Yes, Viton is compatible with many fuels and aromatic/aliphatic hydrocarbons, so these rings are suitable for gasoline and diesel exposure.

Are they safe for high-temperature use?
Yes, they are rated for service from -15 degrees F up to 400 degrees F, making them appropriate for many high-heat applications.

Will they work with brake fluid?
No, Viton is vulnerable to glycol-based brake fluids, so use a different elastomer for brake-system seals.