SSP Manufacturing, Inc
The automotive radial lip seal works by creating a thin layer of oil between the sealing lip and shaft journal. Capillary action causes the oil to seep between the lip and the shaft, which results in the oil lifting the sealing lip clear of the shaft.
This thin layer is retained, and prevents leakage of the oil past the sealing lip.
It is important to ensure that the seal is fitted square in the housing and perpendicular to the shaft and that end float and radial shaft run out is not excessive.