434 Viton O-Ring 75A Durometer, 5-5/8 in ID - Reliable Chemical Seal

Our review of the 434 Viton O-ring finds it best suited to technicians and hobbyists who need a compact, chemically resistant seal that lasts in demanding environments. The single biggest reason to buy is its material: made from genuine Viton fluorocarbon elastomer, this O-ring resists fuels, aromatic and aliphatic hydrocarbons, and many industrial chemicals while operating across a wide temperature span, so it replaces common seals in fuel systems and high-heat applications without frequent failure.

Key Features

• Material: Viton fluorocarbon elastomer provides strong resistance to fuels, oils, ozone, and weathering for longer service life.
• Temperature range: Rated from -15 degrees F to 400 degrees F, allowing use in both low-temperature and high-heat assemblies.
• Durometer: 75A hardness balances compression resistance and flexibility so the ring holds a seal under pressure without excessive deformation.
• Shape and fit: Round cross-section and precise dimensions give a reliable seal between overlapping cylindrical parts in pumps, bottles, and valve stems.
• Compatibility: Works with non-flammable hydraulic fuels, silicone oil, chlorinated and aromatic hydrocarbons, and in high vacuum environments.

Who It's For

This O-ring is ideal for maintenance professionals, gunsmiths, and equipment owners replacing seals on fuel bottles, hydraulic fittings, or barrel assemblies that encounter fuels, solvents, or high temperatures. Customers who value durability and chemical resistance will appreciate the long service life relative to general-purpose elastomers.

Those who need compatibility with strong alkalis, ammonia, glycol-based brake fluids, or super-heated steam should look for a different elastomer, since Viton is vulnerable to those specific chemicals and conditions. Likewise, applications requiring extreme low-temperature flexibility below the specified range may require a different compound.

Pros & Cons

Pros

• High chemical and heat resistance makes it suitable for fuel and solvent-exposed seals.
• 75A durometer provides good wear resistance while maintaining enough elasticity for a tight seal.
• Customers report good fit and leak resistance in common replacement uses like fuel bottles and barrel seals.

Cons

• Not compatible with low molecular organic acids, ammonia, alkalis, glycol-based brake fluids, or super-heated steam.

Specifications

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

Our Verdict

The 434 Viton O-ring is a practical choice for anyone who needs a durable, heat- and fuel-resistant seal at a reasonable price; it excels as a replacement part for fuel bottles, hydraulic fittings, and firearm assemblies where Viton compatibility is required. Buyers should confirm chemical compatibility for aggressive alkalis or steam, but otherwise it represents good value for demanding sealing tasks.

Frequently Asked Questions

Is this O-ring suitable for fuel system use?
Yes. The Viton compound is compatible with many fuels and aromatic hydrocarbons and is commonly used for fuel bottle and non-flammable hydraulic fuel seals.

What temperatures can this O-ring handle?
It is rated for use from -15 degrees F (-26 degrees C) up to 400 degrees F (205 degrees C).

Will it resist all chemicals?
No. While resistant to fuels and many solvents, Viton is vulnerable to low molecular organic acids, ammonia gas, alkalis, amines, glycol-based brake fluids, and super-heated steam.