I have yet to dismantle the needle bar. Betsy took apart Rusty's needle bar, the second vintage sewing machine I bought. We have yet to put that back together. We figured we had nothing to lose, since it was jammed anyway.
In this photo you can see the presser bar bracket (I think that is what it is called) . This will come out with, guess what? Jiggle and Wiggle.
Behind the needle bar is the tension releasing lever with tension releasing spring. When you move the lever up it puts pressure on the little pin inside the tension assembly and frees up the tension when the presser bar is lifted. Pretty clever engineering
|Tension Releasing Lever and spring|