We receive this question quite regularly: Which way do I install this oil seal?

The above picture shows the cross section of a single lipped oil seal. The side with the spring and recess always faces the oil you are trying to contain.



Crank seals on the drive side or primary side are meant to retain the oil level in the chain case. The seal is installed with the spring facing out toward the primary case. The seal actually rides on the engine sprocket shoulder. Removed for photography.


Seals in the timing cover are retaining oil pressure in the cover. An example of this is the timing side crank oil feed seal. The points seal is meant to keep oil away from the contact breaker so it is installed reverse of the feed seal.

Image result for triumph timing cover seal


Gearbox seals retain gear oil so to spring goes towards the inside of the gearbox.


Magneto seals keep oil out of the mag and in engine case to which they are mounted.