365 Viton O-Ring 75A, 7 in ID 3/16 in Width - Heat & Fuel Resistant

In this review of the 365 Viton O-Ring the bottom line is straightforward: this pack of ten is for anyone who needs a durable, chemical- and heat-resistant replacement O-ring that holds leaks under demanding conditions. The reviewer found the most compelling reason to buy is the material - genuine Viton fluorocarbon elastomer - which offers reliable resistance to fuels, aromatic and aliphatic hydrocarbons, ozone and weathering while tolerating service temperatures from -15 degrees F up to 400 degrees F. Fit and durability for common hydraulic and sealing tasks are the decisive benefits highlighted by users.

Key Features

• Material: Made of Viton fluorocarbon elastomer to resist fuels, oils and many harsh chemicals for long service life.
• Temperature Range: Rated for -15 degrees F to 400 degrees F so it remains flexible in cold starts and stable at high operating temperatures.
• Cross-section: Round cross-section provides a reliable seal between overlapping cylindrical surfaces and helps prevent leaks.
• Hardness: 75A durometer offers a balance of compression resistance and resilience for repeated use without quick extrusion.
• Compatibility: Works with non-flammable hydraulic fuels, silicone oil, chlorinated and aromatic hydrocarbons, and is suitable for vacuum and ozone-exposed environments.
• Standard Size: AS568A compliant size suited to common industrial and plumbing replacement tasks where a 7 in ID ring is required.

Who It's For

This product suits mechanics, technicians and hobbyists who need a reliable replacement O-ring for fuel systems, hydraulic fittings, Silencerco switchback-type applications, MSA fuel bottle seals or other cylindrical joints exposed to fuels and heat. The pack of ten is convenient for workshops and repeated maintenance tasks.

Those who should look elsewhere include users needing compatibility with glycol-based brake fluids, strong alkalis, ammonia gas or super-heated steam, since Viton is vulnerable to those media. If a softer or much lower temperature compound is required, choose a material specified for those extremes.

Pros & Cons

Pros

• Excellent chemical and fuel resistance makes these rings reliable in many service environments.
• Wide temperature tolerance ensures the O-rings remain functional from cold starts to high-heat operation.
• Customers report precise fit and good leak resistance in practical replacements for common gear.
• Pack of ten offers good value for routine maintenance and multiple repairs.

Cons

• Not compatible with low molecular weight organic acids, amines, glycol-based brake fluids or prolonged exposure to super-heated steam.
• 75A hardness may be too stiff for applications that demand an extremely soft seal.

Specifications

Brand	Mr O-Ring
Material	Viton (fluorocarbon elastomer)
Durometer	75A
Inner Diameter	7 in
Outer Diameter	7-3/8 in
Cross-section Width	3/16 in
Quantity	Pack of 10

Our Verdict

The 365 Viton O-Ring pack is a sensible buy for anyone needing sturdy, heat- and fuel-resistant replacement seals; its 75A hardness and Viton formulation deliver dependable leak resistance and durability. It represents good value for workshops and field repairs, provided the service fluids do not include incompatible chemicals like strong amines or glycol-based brake fluid.

Frequently Asked Questions

Are these O-rings suitable for fuel system seals?
Yes; the Viton material is compatible with many fuels, aromatic and aliphatic hydrocarbons and commonly used silicone oils, making them suitable for fuel system seals.

What temperature range can these O-rings handle?
They are rated for continuous use from -15 degrees F (-26 degrees C) up to 400 degrees F (205 degrees C).

Will these work with brake fluid?
No; Viton is vulnerable to glycol-based brake fluids, so they should not be used where exposure to those fluids is expected.