The top tension on my 401 doesn't work well. By that, I mean that I cannot tighten the upper tension so that it will pull the bobbin thread up to the place it should be. (No adjustment will make that happen.) The tension has not been worked on since I've had it. Is it just a matter of taking it apart and cleaning it, using a youtube tutorial as a guide? (I've not done one before.) It sews well enough to think that no parts are bent or missing. I just can't get the tension right.
bkay

HI bkay,
Have you checked to make sure the tension stud isn't turning with the knob. It looks like there met be a set screw for it behind the faceplate.

Hi, bkay. If it was me, I would watch https://www.youtube.com/watch?v=UttHpnQy0xk and maybe look at http://sewing-machines.blogspot.com/...djustment.html although this last link looks like some of the back pieces are not illustrated.

Janey - Neat people never make the exciting discoveries I do.
Not affiliated with off-site link(s)

Thanks, Janey. It doesn't look like much of a chore. You always come through. THanks again.
bkay

Have you checked out the bobbin case tension as well? Should be set to 1 oz or about 28 g. There are a couple methods to do this, depending on the equipment you might or might not want to purchase ; ) I have a Kiddie-Sipp tensometer from the 50s because I'm that nerdy Links to simpler methods below...

Matt

https://www.youtube.com/watch?v=bTdSkkC4jtM
https://www.youtube.com/watch?v=gUUFFAn9DSs