Hello,
We'd be happy to look into this for you but we'll need a but more information to get started. First, please show us the pivot shoe that the coil springs attach to, preferably uninstalled. There should also be numbers stamped on the coils that you'll need to determine the corresponding strength options. If not, we'll need to know the exact weight of the window sash to divide by the number of coils in the window. Thank you!
Thanks for getting back to us. If you have Certainteed windows, we offer the 15-192 pivot shoe that uses the S170 and S171 coil springs, along with the parts listed under the related items section of the 15-192 product page. Please note that some customers have reported that they needed to shave the front of the shoe down to install it in their window jamb.
We also offer a conversion video shown below that works for both Certainteed and Simonton windows that use this type of assembly. Take a look and review the full process below to see which option you'd prefer for your repair.