broken bonneville window balance

I think we can help, but I'm afraid I can't confirm based on the stamp alone. All that tells us is how strong the spring is. I recommend that you look at our Channel Balance Home Page and follow the steps in order to find the Series that best matches what you have.

Thanks for the additional information. I recognize this balance. It was made by a company that went out of business, and is no longer made. That said, we should still be able to help. Consider our S795-31 channel balance with stamp of 31E for sashes weighing 29 through 33 pounds. I think you might be able to get this to work as a substitute. However, you would need to take out the 1-1/4" wide shoe that comes with it and replace it with our 1" wide 15-194. What do you think of this solution?

If the Series 795 balance will not work, then I'm afraid we have no other possible replacement. Your old balances aren't made anymore, unfortunately. Since these are wood windows, a local mill work may be able to make new jamb liners for you. These would come with all new springs, and hopefully they'll be more modern.