473 O-Ring Viton 75A 24in ID 24-1/2in OD - High-Temp Seal

In this review the 473 O-Ring made of brown Viton is examined for engineers, home mechanics, and anyone needing a durable chemical- and fuel-resistant seal. The bottom line: this O-ring is ideal when a compact, heat-resistant round seal is required; its primary appeal is the combination of a Viton fluorocarbon elastomer compound with a 75A durometer that stands up to fuels and many chemicals while remaining flexible across a wide temperature range. For applications needing a precise AS568A size and reliable leak prevention, this is a practical, value-minded choice.

Key Features

• Material: Viton construction provides high resistance to fuels, aromatic and aliphatic hydrocarbons, and many industrial chemicals so the seal lasts in harsh environments.
• Temperature range: Rated from -15 degrees F to 450 degrees F, it remains functional in both cold starts and high-heat operating conditions common to engines and industrial equipment.
• Hardness: The 75A durometer balances firmness and elasticity to maintain a dependable seal between cylindrical overlapping surfaces without excessive compression set.
• Cross-section: Round profile gives a consistent sealing surface for static or dynamic interfaces such as injector seats and hose fittings, reducing leakage risk.
• Standardized size: Conforms to AS568A sizing for compatibility with equipment specified to aerospace O-ring sizes, making replacements straightforward.
• Chemical compatibility: Suitable for silicone oil, chlorinated hydrocarbons, and many fuels, which supports use in hydraulic and fuel-system repairs.

Who It's For

This O-ring is a good match for automotive technicians working on diesel injectors, hobbyists replacing garden hose or small pump fittings, and maintenance pros needing a compact, heat-tolerant seal that resists fuel and many chemicals. The specific 24in ID and 24-1/2in OD sizing suits applications where an AS568A-standard O-ring is required.

Those who should look elsewhere include users needing compatibility with strong alkalis, ammonia gas, or low molecular weight organic acids, since Viton can be vulnerable to those substances. Also consider alternative elastomers if a much softer or much harder durometer is required for a specialized dynamic seal.

Pros & Cons

Pros

• High chemical and fuel resistance offers long service life in fuel-system and hydraulic applications.
• Wide operating temperature range provides reliable sealing from cold conditions to elevated engine or process temperatures.
• The 75A durometer delivers a good balance of sealability and durability for static sealing tasks.
• Meets AS568A sizing expectations, easing replacement and compatibility concerns.

Cons

• Viton is not recommended for environments with strong alkalis, ammonia, or certain acids, limiting use in some chemical processes.
• Some customers reported the ring felt thinner than expected for heavy-duty compression applications, so verify thickness needs before purchase.

Specifications

Material	Viton (fluorocarbon elastomer)
Durometer	75A
Inner diameter	24 in
Outer diameter	24-1/2 in
Cross-section / Width	1/4 in round
Color	Brown
Standards	Meets Aerospace Standard AS568A

Our Verdict

The 473 Viton 75A O-ring is a reliable, economical choice for engineers and DIYers needing a heat- and fuel-resistant round seal in AS568A sizing. Its material and durometer make it especially suited to static sealing in fuel, hydraulic, and high-temperature environments; just avoid use with strong alkalis or ammonia. For those seeking dependable leak prevention and chemical tolerance at a modest cost, it represents good value.

Frequently Asked Questions

Is this O-ring suitable for fuel systems?
Yes. Viton has strong resistance to many fuels and aromatic hydrocarbons, making it appropriate for many fuel-system sealing tasks.

What temperatures will it withstand?
The O-ring is rated for operation from -15 degrees F up to 450 degrees F, covering most engine and industrial temperature ranges.

Will it work with harsh acids or alkalis?
Viton is vulnerable to low molecular weight organic acids, strong alkalis, and ammonia gas, so those environments are not recommended.