Oil-seal 

A circular, rubber lipped seal that fits snuggly onto a shaft, keeping oil inside a component for lubrication whilst the shaft rotates.

See how he smites the hammer atop the chisel and deftly taps the oil-seal into place in the hub.

Oil-seal by Penfold2 July 29, 2007

hub oil seal 

A seal to keep oil within a hub of an axle or wheel, preventing loss of said oil onto other components such as brakes, and maintaining lubrication of internal bearings on the axle.

"look how he is fitting that hub oil seal! The deftness of the sledgehammer smiting that chisel."

hub oil seal by Penfold2 July 12, 2007