Identify additional coil balance?

Thanks for posting. While I see you'd think those stamps are indicative of the Series 140, the shape of your coil housing shoes is actually more resembles our 15-087 Shoe and the 15-086 Tandem Housing. This Pivot shoe uses our Series 180 Coil Springs, sold separately. I'm afraid too that the stamps on your old housing won't necessarily tell you what spring weights you need for these coil springs; typically only stamps on the spring tape themselves are reliable. Look for stamps on the coil springs to see what spring weights you need. If there are none, or you are uncertain, weigh your window sash. Give us that exact weight, and we'll tell you what you need.

Thanks for getting back to me. If your sash weighs 13 lbs exactly, and if the coil spring was stamped '7', then our S180-7 7lb coils should work for you, one on each side of the sash. This equals 14 total lbs of support; plus or minus one pound of difference is fine with these coil springs. 

Now, one further thing to point out is that your old pivot shoe has a notch at the bottom of its cam. This is to accommodate the peg in the 26-422 pivot bar. Our 15-087 shoe, however, lacks this notch, so it's possible your old pivot bar won't be compatible with this pivot shoe. You may have to test it out to see. Let us know what you find.