what brand of accordion? If it's a factory made (Hohner, Weltmeister, etc), the springs are not easily findable. If it's a handmade, Louisiana accordion, you need to know what springs the builder used. The LA builders use the same type of springs, as each other, but not all use the same exact springs. Some are shorter, some are longer, some have different girth

Jim brings up a really good point. If you have an Arriette or similar accordion, they use springs that are like safety pins, if LA handmade, Jim already told you.

If you do have one of the non LA accordions, it is virually impossible to replace the springs most of the time because they usually staple in the spring and then glue the accordion together.

The only success I have had with the non LA made accordions is either
1. replacing all with the "cajun type" springs.
2. Using "push springs" that I had to hand cut to the right size and put under each button lever.

DP

I finally found well made (specially made on tension specs) non rusting or oxidizing springs that will fit a Martin, Bon Cajun or Acadian type accordion. Alas they're pretty expensive at around 50 dollar cents a piece. You will need to bend one loop slightly open with a Martin f.i. to get a medium tension on the buttons, giving that resistant feel giving away in a sort of "pop down manner" once you push a little harder, and closing the flappers pretty fast on release. I have to buy them by the 100, but if some one wants a few, mail me. - Nout

I have made the springs from music wire and from a safety pins. The problem with my Arriette is it is a cheap box and the buttons are glued on, so you have to twist them off to pull the rocker lever.

Then you have to align the buttons carefully so they do not stick when you glue them back in.

Also, it is hard to make a spring that has the exact force of the one you are replacing.

Good luck