The window manufacturer Jen-Weld directed me to your website, as this is a 2002 window they no longer carry parts for (the window is series 9980/9980P).
The balance shoe is 1" wide. Will any 1" wide balance shoe from your series 850 balance work? Every time I measure the balance (from the bottom of the shoe to the top of the plastic piece), it comes out to 28.5" long, which doesn't match the sizes on your site for replacing the entire balance. The sash which this balance supports is 26" wide x 31.5" wide (measuring from the outsides of the vinyl frame).
My preference is to replace just the shoe, if that's possible. I don't own a wide variety of tools, and even I could put the balance back together if I had a new shoe. :)
THANKS! for your help,
Elizabeth