Can I Fix This Window?

Hi Steve. Is the main issue that the window can't stay open? If so, then you probably need to just replace your channel balances. We can help you do this, but we'll need to see one removed from the window, with pictures of any stamps on the metal channel and of the nylon attachments at either end. The length of the metal channel, not including those nylon attachments, would also be helpful. See the videos below for removal and replacement details, as well as how to identify your channel balance. Many thanks. 

This appears to be either an S380-27 or S385-27. The only difference between these two balances is the depth of the bottom nylon shoe, or the 'heel-to-toe' measurement, so compare both with your old hardware to see what matches best. Compare an undamaged balance to the image below for reference. For a new stamp option, choose 2640.

Comparison of the S378, S380 and S385 balance shoes.