251 Viton O-Ring 75A Durometer, 5-1/8ft ID 5-3/8ft OD - Pack of 10

In this review the 251 Viton O-Ring (75A) is evaluated for workshop and field sealing tasks where chemical and heat resistance matter most. The bottom line: this pack of ten provides dependable replacements for fuel-contact and high-temperature applications thanks to its Viton construction and a broad service temperature range. It is best for technicians, hobbyists, and maintenance crews who need an O-ring that resists fuels, oils, ozone, and weathering while holding a snug round seal between cylindrical parts.

Key Features

• Material: Made from Viton fluorocarbon elastomer which provides strong resistance to fuels, aromatic and aliphatic hydrocarbons, silicone oil, and many chemicals encountered in hydraulic systems.
• Temperature range: Rated to operate from -15 degrees F to 400 degrees F, allowing use in both cold-start and high-heat environments without rapid degradation.
• Durometer: The 75A hardness balances flexibility and wear resistance to reduce extrusion and maintain a long-term seal under pressure.
• Shape and fit: Round cross-section designed to form a reliable seal between cylindrical overlapping surfaces such as bottles, barrels, and fittings.
• Standards: Conforms to the AS568A sizing standard so it will interchange with other parts specified to that aerospace-derived dimension set.

Who It's For

This product suits mechanics, equipment maintainers, and enthusiasts who replace O-rings on fuel bottles, hydraulic fittings, firearms seals, or other components exposed to fuels, oils, and elevated temperatures. The pack of ten is practical for repeat maintenance and for keeping spares on hand.

Those who need compatibility with strong alkalis, ammonia gas, glycol-based brake fluids, or super-heated steam should look elsewhere, since Viton is vulnerable to those specific chemicals and conditions and may degrade if exposed.

Pros & Cons

Pros

• Excellent chemical and fuel resistance for non-flammable hydraulic fuels, aromatic and aliphatic hydrocarbons, and silicone oils.
• Wide usable temperature range that covers most workshop and field tasks up to 400 degrees F.
• Good leak resistance and durability reported by users when used as replacements in common assemblies.

Cons

• Not suitable for exposure to strong alkalis, some amines, low molecular organic acids, or super-heated steam, which can cause failure.

Specifications

Our Verdict

The 251 Viton O-Ring 75A in a pack of ten is a strong value for anyone needing reliable replacement seals where fuels, oils, and heat are present. Its combination of Viton chemistry, AS568A sizing, and a practical durometer makes it suitable for maintenance shops and field repairs, provided the excluded chemicals are avoided.

Frequently Asked Questions

Can these O-rings be used with fuel and oil?
Yes, they are compatible with many fuels, aromatic and aliphatic hydrocarbons, and silicone oils as noted in the material compatibility.

What temperature range will these O-rings tolerate?
They are usable from -15 degrees F up to 400 degrees F, covering most automotive and industrial service conditions.

Are they compatible with brake fluid or ammonia?
No, Viton is vulnerable to glycol-based brake fluids and ammonia gas, so avoid those exposures.