Finding a replacement coil for tilt windows

Question

One of my window sashes doesn't stay in place and keeps sliding down. These windows were replaced before I got the place and have no markings for the manufacturer or the coil mechanism.
Attached are pictures from the broken coil spring (both sides are broken and the coil is out). I've attached a picture from a window that does stay in place.
Can you please help me identify what parts I need to buy? The coil width is 1/2" (measured on the exposed part). The window sash weights 16 lbs.

Bob · Accepted Answer

Thanks for posting. This looks like the 15-087 Pivot Shoe, which works with Series 180 Coil Balance springs sold separately. The mounting bracket is the 16-024. If the window sash weighs exactly 16 pounds, you would not need additional coils and the 15-086 Tandem Housing--instead you could just use the S180-08 8 pound spring, one on each side of the sash. This would give you 16 pounds of support overall. Let me know if you have questions.

Series 180 coil balance diagram