If it's sewing, albeit sluggishly, you do NOT need to tear that machine apart! If you go to the section of the forums called "For Vintage and Antique Machine Enthusiasts" There is a thread pinned at the top for Muv's videos on cleaning and using antique machines.
I'd be willing to bet that all you have to do is oil the machine and run it...then oil it again and run it some more.
Skip is the KING of cabinet work, send him a PM if you need help with refinishing
(his board name is Glenn)