436 Viton O-Ring 75A Durometer, 5-7/8in ID x 6-3/8in OD - Durable Seal

In this review the 436 Viton O-ring is presented as a straightforward replacement seal for industrial and hydraulic applications where chemical and heat resistance matter most. The bottom line: this pack of ten provides a reliable, high-temperature sealing option for technicians, maintenance crews, and hobbyists who need a tough elastomer that resists fuels and many solvents. The reviewer found the O-ring's material and dimensions make it especially useful for fuel bottle seals, barrel seals, and other cylindrical mating surfaces that demand a consistent round cross-section and stable hardness.

Key Features

• Material: Made of Viton fluorocarbon elastomer, it offers broad resistance to fuels, aromatic and aliphatic hydrocarbons, and many solvents used in industrial settings.
• Temperature range: Rated for use between -15 degrees F and 400 degrees F, the compound suits applications exposed to both low and high operating temperatures.
• Durometer: With a 75A hardness, the O-ring resists penetration and provides a firm sealing surface that holds up under compression and repeated use.
• Cross-section: The round profile creates an effective seal between cylindrical overlapping surfaces and maintains contact under pressure.
• Compatibility note: Works well with non-flammable hydraulic fuels, silicone oil, trichlorethylene, benzene, propane, high vacuum, ozone, and weather, making it versatile for many service environments.
• Pack quantity: Sold in a pack of ten, which keeps spare parts on hand for routine maintenance or multiple identical assemblies.

Who It's For

This O-ring is best for service technicians, maintenance shops, and hobbyists who need a durable seal for fuel systems, hydraulic fittings, and equipment that sees elevated temperatures. People replacing common seals on MSA fuel bottles, Remington 1100 barrel assemblies, or similar cylindrical joints will appreciate the fit and material resistance.

It is less appropriate for systems exposed to strong alkalies, ammonia gas, low molecular organic acids, amines, glycol-based brake fluids, or continuous super-heated steam; those environments require a different elastomer chemistry. If very soft elastomers are needed for delicate, low-pressure seals, a lower durometer compound would be a better choice.

Pros & Cons

Pros

• Excellent heat and fuel resistance due to the Viton material, which reduces degradation in demanding environments.
• Consistent sizing and round cross-section that customers report fit well for common replacement uses like fuel bottle and barrel seals.
• Pack of ten provides value and spares for routine maintenance or multiple fittings.

Cons

• Not compatible with certain chemicals such as ammonia, alkalis, amines, and glycol-based brake fluids, limiting use in specific service conditions.

Specifications

Material	Viton (fluorocarbon elastomer)
Color	Black
Inner diameter (ID)	5-7/8 in
Outer diameter (OD)	6-3/8 in
Width / cross-section	1/4 in
Durometer	75A
Temperature range	-15 degrees F to 400 degrees F (-26 C to 205 C)

Our Verdict

The 436 Viton O-ring is a solid, no-fuss replacement for users who need a resilient seal that tolerates heat, fuels, and many solvents. For most maintenance tasks and fuel-system repairs it offers good value in a pack of ten, but installers working with aggressive alkalis or amines should select a different elastomer.

Frequently Asked Questions

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

Can it handle high temperature applications?
Yes, it is rated for continuous use up to 400 degrees F (205 C), which covers most high temperature sealing needs short of super-heated steam.

Will it resist weathering and ozone?
Yes, Viton offers good resistance to ozone and weathering, which helps maintain seal integrity in exposed environments.