Universal Joint Boot Covers

Keeping universal joints fully lubricated reduces friction, wear and heat generation and can significantly prolong the useful life of the assembly.

If pre-lubrication, such as in needle-bearing joints, or continuous lubrication with oil drips for example is not attainable, the joints can be fitted with lubricant-retaining boots (bellows). In addition to maintaining component lubrication, boots can prevent contaminants entering and damaging the joints in environments polluted with chips, dirt, acids and/or other abrasives. Since boots retain the lubricants, they can also prevent contamination of the environment by keeping the lubricant contained within the boot.

Standard boots are typically manufactured from Nitrile. However, special operating environments might require other boot materials and lubricants. For instance, if the universal joint operates in a vacuum environment, boots might collapse or the lubricant might gas out; in such and similar instances, metal boots may offer the ideal alternative solution.

Some boot materials are more heat resistant than others. Extreme high and low temperatures can cause changes in the material’s composition as well as make the boots contract and expand past an acceptable range. Boots can also crack at low temperatures or swell if submerged in fuel or exposed to other harsh chemicals. Such issues can cause oils from the grease to seep through the silicone. For such operating conditions the development of alternative boot materials or special design engineering solutions may be necessary.


  • Nitrile (standard), also known as Buna-N, has excellent resistance to petroleum-based oils and fuels, silicone greases, hydraulic fluids, water and alcohol. It possesses high tensile strength and high abrasion resistance. Silicone boots are recommended for high temperature applications.
  • Silicone (-SL) is resistant to high, dry heat. It is also fungus resistant, odorless, tasteless and non-toxic. It has a high resistance to the aging effects of both sunlight and ozone.
  • Neoprene (-CR) was developed as an oil-resistant substitute for natural rubber. It features moderate resistance to petroleum oils and good resistance to ozone, sunlight, and oxygen aging. It has good resilience and is highly resistant to Freon® and Ammonia.
  • Viton (-VT) combines high temperature toughness with wide chemical agent compatibility. It features excellent resistance to petroleum products and solvents.
  • EPDM (-EPDM) has excellent ozone and chemical resistance. Effective resistance to steam up to 400 degrees Fahrenheit, hot water, silicone oils and greases, diluted acids and alkalis, alcohols and automotive break fluids.
Features & Benefits: 
  • Component Protection
  • Continuous Lubrication
  • A Broad Selection of Materials



(708) 344-4600
4100 Madison Street
Hillside, IL 60162

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