Well, a thin coating of gasket making/sealer material may have helped the gasket seal. Then too, the surfaces needed to be clean and even (flush).
Are you sure the unit is not leaking out at the hole in the bottom of the housing that is there for that purpose. The pulley will sling the water everywhere.
If the shaft is not leaking, you may want to take it back off and redo it using a small amount of sealer such as Permatex. You can make a new gasket using a small ball peen hammer (round side for bolt holes and heavy contours) and some suitable gasket material. Real easy.
Charlie
