The dials do not get any oil or grease or heat. They are not the problem. The little posts with the notches and the little thing that goes in and out are prone to freeze up with dried on oil that you can't see. You will need to clean those places thoroughly.

I will try and post a picture. The dial is stuck between the A and B. The plate thingy that is controlled by the stitch selector moves freely now. The other side moves freely too. Well I have to use two hands to hold it in position but it is easy to do.

[QUOTE=miriam;5950806]The dials do not get any oil or grease or heat. They are not the problem. The little posts with the notches and the little thing that goes in and out are prone to freeze up with dried on oil that you can't see. You will need to clean those places thoroughly.[/QUOTE

Okay. Need to get some solvent.

That little horizontal pin is easy to miss and hard to locate the first time - it throws everything off if it has one little teeny tiny dried up piece of oil - I clean it first thing when I do the top of the machine - q-tip and solvent. Protect the area with cosmetic pads or panty liner pads to absorb solvent - also swab out with a q-tip when you are done - I use forceps to get the q-tip down in there... and forceps to get the pads out. After it has been clean you will have to re-oil it. The knob will not turn if those posts with all the slots are gunked up - some times it it the under side of the thingy that rests in the notches. Pushing in or pulling out pulls that little thingy out of the grooves. If there is gunk you won't be able to work the knobs. You can't see that dried up oil - even a tiny drop will keep it from moving. There is a reason the repair man wants $179 to do this kind of clean up job. Some times it takes hours. Some times it takes days. You have to be very thorough and even then some times you miss something. A few weeks ago I missed something dried up in the gears under the bobbin area somewhere. It doesn't take much dried up oil to stop up one of those Singer 401 machines.

BTW I run my 403 all the time with out the cam on there. Never had a problem - I don't get it I guess. I think it is the Singer 328, 319 etc - some other old machines you have to worry about.

I don't know what you are saying.

You probably have solvent around - brake cleaner, zylene, denatured alcohol, gun cleaner - be VERY careful - those can ruin your paint and if you breathe the vapors they can damage your liver. Joe says gun cleaner maybe safe - I don't have any handy.

I had to laugh. I don't know what I am saying either! The stitch selector knob on the left side is stuck upwards between the A and B. There is a piece about an inch square that is on the left of the cam stack and moves when I move the red stitch selector on the front of the machine. I can get the other stitch selector dial to move pretty freely. No solvents around. But will get some.

OKAY!!!!! Look down below that square thingy you just mentioned and between the cam stack - there should be a horizontal pin - clean it with solvent. If you push on the needle bar about where the little square thingy is - it should move that pin in and out side to side.

There is a spring comes off once in a while and you have the readers go places they shouldn't - you won't be able to fix that if it has - not with out another 401 right next to you or good pictures. Shoot a picture so we can help you figure out what is going on. I need a good clear shot of the top of the machine - like the one where we show the oil places. Your problem is NOT the knob. Don't worry about that knob for a little while. There is something stuck, a spring off of it or some dried piece of oil you haven't found.

Here is a picture of the innards of my 401

It looks like your problem is NOT the spring - relief.
Do the knobs pull out or push in at all?