Posted on June 07, 2022

What is the Best O-ring Material for Hydraulic Fluid?

John Joyce
Written by

John Joyce

Posted in
Fittings, Tube Fittings

Hydraulic fittings incorporating O-rings are not new to the market. While O-rings provide a simple solution, they are often taken for granted. Important characteristics of the O-ring, such are material selection, are frequently ignored. In this blog post, we’ll discuss the types of materials available to help you choose what’s best for your application.



Buna-N (Nitrile) is the most common type of material used in quick-acting couplings. It provides a great seal and is commonly used in crude oil, gasoline, propane, petroleum oils and water. This type of O-ring performs best in temperatures ranking from 40 to 250-degrees Fahrenheit.

Peroxide-cured Ethylene Propylene Diene Rubber (EPDM)

For medical grade polypropylene couplings, EPDM is often used in medical devices, automotive manufacturing, water and wastewater systems. This type of O-ring resists attack from most chemicals and holds up in challenging applications.


For a strong and dependable O-ring, FFKM (Kalrez) can have a long service life and can be highly resistant to extreme temperatures, pressure and chemicals. Therefore, these O-rings are great for harsh environments.


Fluorocarbon (Viton) O-rings are used for applications where there are extreme temperatures and chemicals. Providing resistance to ozone, oxygen, mineral oil, synthetic hydraulic fluids, fuels, aromatics, etc., these O-rings are ideal for fuel lines.


Silicone O-rings are good in temperatures ranging from 70 to 400-degrees Fahrenheit. They are commonly used in medical devices, food storage products, electronics and automotive applications since they are odorless and non-toxic.

In conclusion, O-ring fittings can eliminate leaks in a hydraulic system when used correctly. They are frequently designed for specific applications, so you must be careful when choosing a fitting that has an O-ring.

Learn more about why “Your Connection is Only as Good as Its O-ring” by downloading our white paper.

Download Your O-Ring Whitepaper


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