Hi there, Ian.
We'd be happy to help with this project but I'm afraid I can't ID what you may have. I would need you to remove an undamaged pivot shoe and show us some photos. In the meantime, take a look at the videos we've related for you on this page and let us know if they help.
It's not possible for us to identify your hardware from these photos, unfortunately. In order to help, we need to see the pivot shoe removed from the window. I know that's not ideal but I'm afraid the track just obscures too much of the hardware.
Thanks for the additional photo, Ian! It's a huge help. Based on what I see here, I recommend the 15-087 pivot shoe. We also sell the 15-086 housing but you can reuse your old one if it's in good shape. The Series 180 are the compatible coil springs.
I also recommend checking the band of the spring for a stamped number that would indicate the weight. If there aren't any, you'll have to divide the precise sash weight by the total number of springs in the window to determine the proper weights.
Yep, if the pivot shoe and housing are in good shape you can just reuse them. You may need the S180-5 5-pound spring based on your stamp. You can always weigh your window sash on a scale to confirm if you want to be 100% sure.
Yes, that is correct! The sash should indeed weigh 20 pounds if there's a total of 10 pounds of support on both sides.
