388 Viton O-Ring 75A, 19 in ID 19-3/8 in OD - Durable Sealing Pack

In this review the 388 Viton O-Ring is evaluated for routine repair and maintenance uses where chemical and heat resistance matter. The bottom line: this pack of 100 rings is best for technicians, hobbyists, and maintenance teams who need a reliable, heat- and fuel-resistant replacement O-ring in a common round cross-section. The single biggest reason to buy is material performance - made from Viton fluorocarbon elastomer, these O-rings stand up to high temperatures and many fuels that would degrade ordinary rubber.

Key Features

• Material: Viton construction provides excellent resistance to fuels, aromatic and aliphatic hydrocarbons, and many chemicals, extending service life in harsh environments.
• Temperature range: Rated from -15 degrees F to 400 degrees F, the material can be used across wide thermal conditions without rapid hardening or softening.
• Durometer: A shore hardness of 75A gives a balance of elasticity and resistance to penetration for reliable sealing under compression.
• Shape and fit: The round cross-section is designed to form a consistent seal between overlapping cylindrical surfaces and is suitable for common applications such as fuel bottle and barrel seals.
• Standards: Manufactured to meet AS568A dimensions, helping ensure interchangeability with standard sizes and predictable fit.
• Value pack: Supplied as a pack of 100, making it economical for repeated replacements and inventory for maintenance shops.

Who It's For

This product is aimed at industrial maintenance crews, gunsmiths, and users replacing seals on fuel systems or mechanical assemblies who require chemical and heat resistance. Its compatibility with non-flammable hydraulic fuels, silicone oil, chlorinated and aromatic hydrocarbons makes it useful where conventional elastomers fail.

Those who should look elsewhere include users who need compatibility with strong alkalis, ammonia gas, glycol-based brake fluids, or super-heated steam, since Viton is vulnerable to these media. Also choose a different material if you require flexibility below -26 degrees C or a much softer or harder durometer than 75A.

Pros & Cons

Pros

• High chemical and fuel resistance provides durable performance in demanding environments.
• Wide usable temperature range supports use from cold storage to high-heat machinery.
• Pack of 100 offers cost-effective replenishment for frequent maintenance tasks.
• Meets AS568A sizing for easier replacement and predictable fit in common applications.

Cons

• Not compatible with ammonia, strong alkalis, amines, glycol brake fluids, or super-heated steam, limiting some specialty applications.
• 75A hardness may be firmer than ideal for some low-pressure, soft-seal needs.

Specifications

Our Verdict

The 388 Viton O-Ring pack is a practical, cost-effective choice for repair shops and users needing a reliable, heat- and fuel-resistant seal. Its combination of Viton chemistry, 75A hardness, and AS568A compatibility make it a smart buy for most fuel, hydraulic, and general sealing tasks, though those needing resistance to strong alkalis or glycol brake fluids should select a different compound.

Frequently Asked Questions

Are these O-rings suitable for fuel applications?
Yes. Viton is compatible with many fuels, aromatic and aliphatic hydrocarbons, and non-flammable hydraulic fuels listed in the product notes.

Will they fit standard AS568A grooves?
Yes. The rings meet AS568A dimensions and are intended to be interchangeable with standard sizes in that series.

Can they be used with brake fluid or ammonia?
No. Viton is vulnerable to glycol-based brake fluids and ammonia gas, so an alternate seal material is recommended for those fluids.