This looks like an old thread on here. You don't really have to totally disassemble a sewing machine to put it in working order.
Muv has some nice videos for cleaning and fixing up sewing machines.
http://www.quiltingboard.com/vintage...v-t167789.html I first found these videos from a Google search I did trying to find more info because I thought the machines did not need to always be disassembled to get them to run. Then I discovered Muv was a QB member!!!! Grab a nice cup of tea and enjoy her videos!!! This is really good info!