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IDENTIFY OIL SEAL TYPES

"HOW CAN I DETERMINE WHAT TYPE OF OIL SEAL I NEED?"

Oil seals (or rotary seals) come in a range of materials and types, some of the most common materials we are asked for are: nitrile, highly saturated nitrile, Viton®, silicone and PTFE. Our website listings are for Nitrile and Viton®, but we are able to source and supply the above and more, on demand.

Oil seals can be difficult to get right, especially if you do not have the original machine specifications to advise. There are a few ways to identify oil seals, from the design of them, size and material. With hundreds of different oil seals available on the market, we offer as standard the four most common design types: Nitrile or Viton® material, in either single or double lipped. How to determine your seal can be found below.

Nitrile oil seals (also known as acrylonitrile butadiene rubber seals or NBR) are the most commonly used material and are a very good general purpose use to to the flexibility of use across a range of different components. Nitrile has a strong resistance against fats, hot water, gasoline and different oils. The temperature range of nitrile oil seals is fairly narrow, generally between -30°C to 100°C, meaning nitrile oil seals are a bad choice for components seeing extreme temperature changes. Nitrile will generally be black in colour, but other colours can be sourced if necessary, this is how to differentiate between materials. See below image.

Viton® oil seals (also known as FKM) are fluorocarbon based fluoroelastomer material, containing vinylidene fluoride as a monomer. Viton® seals are best suited for diverse sealing jobs that require high temperature and chemical resistance, being able to withstand temperatures between -20°C to 210°C. Viton® seals will generally be brown in colour, or have FKM stamped on the top of the seal. See below image.

 

"The primary function of an oil seal is to protect & enhance the life span of bearing systems by retaining the lubricant, overall reducing friction."

R1 - An R1 oil seal is a totally metal encased seal, generally with a nitrile lip. The outer metal shell can be offered in mild steel, or stainless steel, whilst the inner lip can be offered in nitrile, Viton®, PTFE and leather.

R4 - An R4 oil seal is a single lipped, metal cased seal. The single lip can be offered in either nitrile or Viton® and comes with a spring type sealing lip.

R6 - An R6 oil seal is a double lipped, metal cased seal. The double lip can be offered in either nitrile or Viton® and comes with a spring type sealing lip.

R21 - A R21 oil seal is a single lipped, rubber coated seal with a metal inner. The seal can be offered in nitrile, Viton® and silicone and comes with a spring type sealing lip.

R23 - A R23 oil seal is a double lipped, rubber coated seal with a metal inner. The seal can be offered in nitrile, Viton® and silicone and comes with a spring type sealing lip.

"SO, NOW I HAVE DETERMINED THE MATERIAL AND TYPE OF OIL SEAL, HOW DO I KNOW THE SIZE?"

Once you have determined the type of seal you are after, you would need to let us know the size of the seal. Most seals will have numbers written on them, generally, these are your metric sizes in the order of inner diameter, outer diameter, width. See image below highlighting the numbers stamped onto the oil seal. If you are unable to read the numbers on your seal, simply get a vernier and measure the inside diameter, outer diameter and the width.

Last Modified: 11th Oct 2021