For more detailed information, please see the following:

Names and functions of seal components　

Finding the right rubber oil seal for your application

Indeed, when installing this oil seal, the oil sump must be installed using silicone seal. Removal of the old seal and oil sump is necessary, otherwise the oil seal cannot be fitted properly either. If these steps are not followed, leakage is inevitable.

First, an elastomer, most often nitrile, is vulcanised to a metal ring. This creates a stiffening effect that includes a specialised metal tension spring directly behind the sealing lip, keeping the oil seal firmly in place against the moving part.

Oil seals have a flexible lip that actually rubs against the rotating shaft or housing to prevent leakage. The spring keeps the lip in contact with the shaft. Bearing isolator oil seals are dynamic seals that incorporate a rotor or rotating member and a stator or stationary member. The rotor actually turns with the shaft. Some oil shafts are bearing isolators with a labyrinth construction. Others incorporate simpler O-rings.