M5x75 Viton O-Ring 75A Durometer, 75 mm ID - Durable Seal

In this review the M5x75 Viton O-Ring is evaluated for technicians, mechanics, and hobbyists who need a reliable metric seal that resists fuels and many chemicals. The bottom line: this pack of ten O-rings stands out for its material choice and temperature range, offering a practical solution when compatibility with non-flammable hydraulic fuels, silicone oil, and many hydrocarbons is the priority. It is particularly useful where a firm 75A hardness and a 75 mm inner diameter are required to maintain a durable seal under varied operating conditions.

Key Features

• Material: Made of black Viton fluorocarbon elastomer, it offers superior resistance to oils, fuels, and many industrial chemicals compared with general-purpose elastomers.
• Durometer: The 75A hardness balances flexibility and compression set resistance so the O-ring holds a consistent seal without being overly stiff.
• Temperature range: Rated for a wide operating range, it remains functional from low temperatures up to high heat, making it suitable for varied environments.
• Cross-section: The round profile provides a dependable seal between cylindrical overlapping surfaces, ideal for threaded barrels and circular fittings.
• Compatibility: Works with non-flammable hydraulic fuels, silicone oil, aromatic and aliphatic hydrocarbons, and is suitable for high vacuum applications where chemical stability matters.

Who It's For

This O-ring is best for users who need a chemical- and heat-resistant seal in industrial, automotive, or motorcycle applications, such as sealing threaded barrel protectors, carburetor seat seals, or hydraulic fittings. It also suits maintenance shops and fabricators who require consistent dimensions and a mid-range hardness.

Users who should look elsewhere include those needing compatibility with strong alkalis, ammonia gas, or glycol-based brake fluids, and anyone requiring extreme low-temperature elastomers beyond the stated range; alternative elastomers are preferable in those cases.

Pros & Cons

Pros

• Good chemical resistance from the Viton compound provides durability in fuel- and oil-exposed applications.
• 75A durometer offers a practical balance of flexibility and sealing force for threaded and cylindrical interfaces.
• Positive customer feedback highlights reliable fit, seal quality, and value for money for common uses like Springfield threaded barrels and carburetor seats.

Cons

• Not compatible with certain chemicals such as ammonia, strong alkalis, and glycol-based brake fluids, limiting use in some specialized systems.
• The stated high-end temperature rating varies in descriptions; confirm your application's maximum service temperature before use.

Specifications

Material	Viton (fluorocarbon elastomer)
Durometer	75A
Shape	Round cross-section O-ring
Inner diameter (ID)	75 mm
Outer diameter (OD)	85 mm
Width / Cross-section	5 mm
Temperature range	-15 degrees F (-26 degrees C) to 400 degrees F (205 degrees C)

Our Verdict

The M5x75 Viton O-Ring is a sensible buy for those needing a mid-hardness, chemically resistant seal in industrial or automotive contexts; the pack of ten and reliable sizing deliver good value. Avoid it only when exposure to incompatible chemicals or extreme temperature endpoints rules out fluorocarbon elastomers.

Frequently Asked Questions

Is this O-ring suitable for gasoline and hydraulic fluids?
Yes; Viton is compatible with many fuels and non-flammable hydraulic fluids listed, making it suitable for such uses.

Will the 75A hardness be too stiff for small precision fittings?
Not usually; 75A provides a balance of flexibility and seal force, but very delicate fittings may prefer a softer elastomer.

How many O-rings are included?
This product is sold as a pack of ten O-rings.