Next, apply a small amount of grease to the seal lip(s) and the area of the shaft in contact with the seal. When using a double-lip seal, fill the small cavity between the two lips with grease as well. This both protects the lips during initial installation and break-in, and also acts as another barrier keeping contaminants out. When installing rubber-coated seals, apply lubricant to the outside diameter as well. This will help prevent the seal from rebounding or backing out from its mounting place.
(5) The surface finish of the shaft directly affects the service life of the oil seal, that is, the higher the shaft finish, the longer the service life of the oil seal.