There are three kinds of Zenith Power Front Motors. Currently there are No NEW power front motors for the Most common failure are available for sale,used on Zenith tables from 1984 to 2003. The the makers of that Zenith II Power Front Motor had shut their doors, without making replacements available.
This is ONE MIDDLE MOTOR COVER replacement ( see Diagram )
This is the small silver Power Front motors pictured (originally used on Zenith tables from1984 to 2003).
Zenith II Power Front Cover,Zenith II Power Front Middle Cover, Zenith II Power Front Cover for sale, Replacement Zenith Power Front Upper Cover