426 Viton O-Ring 90A, 4-5/8in ID 5-1/8in OD - Pack of 10

In this review the Mr O-Ring 426 Viton O-Ring pack is assessed for workshop and industrial sealing tasks; the bottom line is that these are a robust, high-temperature choice for mechanics and technicians who need dependable chemical and heat resistance. The reviewer found the 90A durometer Viton (FKM) material performs well where fuels, oils, and high temperatures are present, and the pack of 10 provides enough spares for routine maintenance. The product is best chosen when compatibility with petroleum, diesel, biodiesel blends, silicone oils, or high vacuum and ozone exposure is required.

Key Features

• Material: 426 Viton (FKM) construction gives excellent resistance to fuels, oils, hydraulic fluids and many solvents so seals last longer in aggressive environments.
• Temperature range: Rated from -26C (-15F) to 232C (450F), enabling use in both cold starts and sustained high-heat service without rapid degradation.
• Durometer: 90A hardness provides a firm compression set resistance that holds sealing force well in flanges and gland applications.
• Size accuracy: Nominal and actual dimensions are listed (4-5/8in ID nominal; actual 4.600in ID) which helps installers match to AS568 size standards without guesswork.
• Pack quantity: Ten o-rings per pack supply spare parts for maintenance cycles or multiple assemblies, reducing downtime when replacements are needed.

Who It's For

The Mr O-Ring 426 Viton is aimed at maintenance technicians, HVAC and hydraulic service professionals, and hobbyists who need a durable o-ring for fuel, oil, and high-temperature sealing applications. Its compatibility with petroleum, methanol or ethanol blends, diesel and biodiesel, and silicone oils makes it a practical choice for automotive, marine, and industrial equipment.

Those who should look elsewhere include users needing soft, low-durometer seals for delicate compression or very low-pressure static seals, and buyers who require non-fluorocarbon materials for specific chemical compatibility not listed here. For metric-only specification projects, confirm size fits before purchase.

Pros & Cons

Pros

• High chemical and temperature resistance from the Viton (FKM) compound extends service life in harsh fluids and hot air.
• 90A durometer offers reliable sealing and resistance to extrusion in moderate to heavy compression applications.
• Clearly listed nominal and actual sizes reduce fitting errors when matching to AS568 size ranges.
• Pack of 10 gives good value for maintenance needs and spare parts supply.

Cons

• Higher durometer means the o-ring is firmer and may not seal as easily in very light-pressure or delicate shafts.
• Viton is not ideal for every chemical; confirm compatibility for uncommon aggressive chemicals before use.

Specifications

Material	Viton (Fluorocarbon rubber, FKM)
Durometer	90A
Nominal ID / OD / CS	4-5/8in ID, 5-1/8in OD, 1/4in CS
Actual ID / OD / CS	4.600in ID, 5.150in OD, 0.275in CS
Metric dimensions	116.84 mm ID, 130.82 mm OD, 6.99 mm CS
Temperature range	-26C (-15F) to 232C (450F)
Pack quantity	10 o-rings

Our Verdict

For professionals and serious DIYers who need an o-ring that withstands fuels, oils and sustained heat, this 426 Viton 90A pack is a practical, cost-effective choice. The defined nominal and actual sizes and the broad temperature and chemical resistance make it a reliable replacement in many hydraulic, fuel and industrial sealing tasks, though users needing very soft seals should consider a lower durometer option.

Frequently Asked Questions

Are these o-rings compatible with diesel and biodiesel blends?
Yes, the Viton compound is specified for performance with diesel and blends with biodiesel as listed in the product details.

Do the listed sizes follow a standard sizing chart?
Yes, the rings are offered to meet AS568 size definitions with both nominal and actual dimensions provided to aid selection.

What is the usable temperature range for these o-rings?
They are rated from -26C (-15F) up to 232C (450F), suitable for most high-temperature sealing needs.