Non-tilt window balance replacement

Question

I have a window with both balance sashes broken. They both failed with a broken top pin (holds top of spring) and broken string at roller.

Looks to be a series 351 I believe, but please verify with the attached pictures. 34" channel length, 1/2" width, 3320 for weight, and bottom shoe piece is 1" deep (see pic).

Thanks!

Bob · Accepted Answer

Thanks for posting, and thanks for all the thorough information. So long as the bottom shoe is 1" deep, then I totally agree--the S351-34, stamped 3320, seems best. It does look 1" deep in your photo; but pictures of measuring tape can sometimes be deceiving, so do double and triple-check to be safe. The only alternative, as you may already have gathered, is the S390-34, which looks just like the Series 351 but has a shoe that is 1-1/8" deep instead. Otherwise, you should be good to go. Let me know if you have further questions!

Comparison of the S351 and S390 balance shoes.