Leather
The sealing element found in most early seals was leather, before the development of synthetic materials. It is tough, resists abrasion, and will work satisfactorily even today in many dirt exclusion applications. However leather is expensive and can usually be satisfactorily replaced with other material.
Advantages
- Tough
- Good tensile strength and abrasion resistance
- Performs well with little lubrication
- Tends to smooth rough shaft surfaces
- Compatible with most lubes and solvents
Disadvantages
- Poor resistance to water
- Its non homogeneous matrix makes consistent high quality performance in production difficult
- Expensive
Operating range
Handles temperatures from -100 °F to 200 °F in some applications. Safer range is -65 °F to 200 °F.
Identification
It’s sometimes difficult to determine from the appearance of a used seal whether the sealing element is leather or rubber. If scratching the surface makes it much lighter-brown or beige and fibrous instead of black and smooth-it’s leather.
If the seal has been charred by overheating, identifications will be even more difficult. However, you can assume the application is to hot for a leather sealing element.