Mr O-Ring 395 Viton O-Ring 90A Durometer, 26in ID - Durable Seal

In this review the Mr O-Ring 395 Viton O-Ring is examined for installers and maintenance technicians who need a high-temperature, chemical-resistant seal in a standard AS568 size. The bottom line: this single-pack Viton o-ring delivers reliable performance across fuels, oils and elevated temperatures thanks to its 90A durometer and fluorocarbon composition, making it a practical choice when compatibility and heat resistance matter more than buying in bulk. The reviewer found the nominal and actual dimensions consistent with expectations for close-tolerance sealing work.

Key Features

• Material and resistance: Made of Viton (fluorocarbon rubber), it offers strong resistance to fuels, mineral oils, silicone oils and many organic solvents to reduce seal failures in harsh environments.
• Temperature range: Rated from -26C to 232C, the o-ring accommodates both very low and very high temperature service without significant hardening or decomposition.
• Durometer: The 90A hardness provides a firm cross-section that is suitable for static and some dynamic sealing applications where a stiffer material improves extrusion resistance.
• Standards and sizing: Sized to meet AS568 standards with nominal 26in ID and precise actual dimensions, helping installers swap into existing grooves and hardware accurately.
• Versatile compatibility: Performs well with diesel, biodiesel blends, methanol or ethanol blends and many acids, making it useful across fuel systems and chemical service.
• Shelf life: Effectively unlimited shelf-life for storage, so spare parts inventories remain usable over long maintenance cycles.

Who It's For

This o-ring is best for professional plumbers, equipment technicians and industrial maintenance staff who need a single, reliable Viton seal in the AS568 equivalent 26in ID range for repairs or prototyping. Its temperature and chemical resistance make it a sensible choice for fuel systems, hydraulic components and high-temperature housings.

It is less appropriate for users who require softer sealing materials for very delicate dynamic shafts or for those who need large multi-packs for production assembly, since this listing is a pack of one and 90A hardness is relatively firm.

Pros & Cons

Pros

• High chemical and heat resistance from Viton (FKM) material reduces the risk of swelling or degradation in fuel and oil service.
• Precise actual dimensions (25.940in ID, 26.360in OD, 0.210in CS) aid in replacing worn seals without guesswork.
• 90A durometer gives good extrusion resistance for demanding static seals.
• Unlimited shelf-life makes it convenient to keep a single spare in inventory.

Cons

• Single-piece packaging may not suit users who prefer bulk quantities for repeated production use.
• 90A hardness can be too firm for some sensitive dynamic sealing applications that require softer materials for shaft conformity.

Specifications

Brand	Mr O-Ring
Material	Viton (FKM)
Durometer	90A
Nominal dimensions	26in ID, 26-3/8in OD, 3/16in CS
Actual dimensions	25.940in ID, 26.360in OD, 0.210in CS
Metric dimensions	658.88 mm ID, 669.54 mm OD, 5.33 mm CS
Temperature range	-26C (-15F) to 232C (450F)

Our Verdict

The Mr O-Ring 395 Viton O-Ring is a solid choice for field repairs and maintenance when compatibility with fuels, oils and high temperatures is required. Its accurate dimensions and Viton resistance deliver dependable sealing for industrial and automotive systems, though buyers who need softer materials or bulk quantities should consider alternatives. Overall it represents good value as a single, reliable replacement part.

Frequently Asked Questions

Is this o-ring compatible with diesel and biodiesel?
Yes. The Viton formulation performs well with diesel and biodiesel blends according to the product description.

Will the 90A hardness work for dynamic shaft seals?
It can be used in some dynamic applications, but the 90A durometer is relatively firm and may not conform as well as softer compounds on delicate shafts.

Does the product meet common sizing standards?
Yes. The o-ring is offered to meet AS568 size standards with both nominal and actual dimensions provided for accurate replacement.