364 Viton O-Ring 75A Durometer, 6-3/4 in ID - Pack of 5

In this review the 364 Viton O-ring (pack of 5) is evaluated for mechanics, hobbyists, and maintenance techs who need a dependable seal that resists fuels, heat, and many chemicals. The bottom line: this is a practical replacement O-ring when compatibility with hydrocarbon fuels and high temperatures matters most, because its fluorocarbon construction and 75A hardness deliver durable sealing over a broad temperature range while fitting common cylindrical overlaps precisely.

Key Features

• Material: Made of Viton fluorocarbon elastomer for superior resistance to fuels, aromatic and aliphatic hydrocarbons, and many chemicals, reducing seal failure in aggressive environments.
• Temperature range: Rated from -15 degrees F to 400 degrees F, allowing use in both cold-start and high-heat applications without rapid degradation.
• Durometer: 75A hardness provides a balance of flexibility and puncture resistance for durable sealing under compression and repeated use.
• Shape and fit: Round cross-section and specified dimensions ensure a tight seal between overlapping cylindrical surfaces and straightforward replacement in compatible parts.
• Standards: Manufactured to meet Aerospace Standard AS568A sizing conventions, so it is easy to match to existing AS568A-based O-ring grooves.

Who It's For

This pack is aimed at technicians, gun owners replacing barrel seals, and equipment maintainers who need an O-ring that handles fuel, silicone oil, and harsh solvents while resisting heat and ozone. It is particularly useful as replacement parts for fuel bottles, hydraulic fittings, and applications exposed to aromatic or aliphatic hydrocarbons.

People who routinely need seals for glycol brake fluids, strong alkalis, ammonia gas, or super-heated steam should look elsewhere, since Viton is vulnerable to those specific chemistries. Also, if a softer or harder shore durometer is required for a particular groove fit, select a different hardness grade.

Pros & Cons

Pros

• Excellent chemical and fuel resistance, making it suitable for many engine and hydraulic uses.
• Wide operating temperature span for reliable performance from cold conditions up to high heat.
• Customers report good fit and leak resistance in common replacements, indicating reliable sizing and function.

Cons

• Not compatible with glycol-based brake fluids, strong alkalis, and some low molecular weight organic acids, limiting use in those systems.

Specifications

Our Verdict

The 364 Viton O-ring pack is a sensible buy for anyone needing a heat- and fuel-resistant replacement seal that holds up in demanding conditions. Given its 75A hardness, AS568A sizing compatibility, and proven leak resistance in customer reports, it represents strong value for repair and maintenance tasks where Viton compatibility is required.

Frequently Asked Questions

Is this O-ring suitable for fuel systems?
Yes, Viton is compatible with many fuels and aromatic or aliphatic hydrocarbons, making it suitable for many fuel system seals.

What temperatures can it handle?
The material is rated for service from -15 degrees F up to 400 degrees F.

Will it resist brake fluid and ammonia?
No, Viton is vulnerable to glycol-based brake fluids, ammonia gas, and strong alkalis, so avoid those fluids.