Radial shaft seals, also known aslip seals, are used to seal rotary elements, such as a shaft or rotating bore Common examples include strut seals,hydraulic pump seals, axle seals, power steering seals, and valve stem seals. Early radial shaft seals utilized rawhide as the sealing element, and many elastomeric seal companies today once were tanneries.he seal construction will consist of a sprung main sealing lip which has a point contact with the shaft. The point contact is formed by two angles, with the air side angle usually less than the oil side angle. In order to exclude contaminants numerous types of dust lips or exclusionary lips may be used. Common elastomers include FKM,NBR,HNBR, and FOM. In order to resist wear, the compounds’ durometer (hardness) is typically 70 to 85 Shore A (between that of an automobile tire and a soft inline-skate wheel)