Sash Windows are "Mastic", from the late 70's

Hello! We can definitely help. The part in question is called a pivot shoe. Yours in particular may not be made anymore, but it's very similar in design to our 15-175. Look over our pictures and dimensions to see how well they line up.

I'm afraid not. The only function of a shoe is to give the coil balance springs a method by which they can support the sash. You see, the balance springs are what keep the sash up when you open it. The springs screw to the pivot shoe and then the pivot shoe cradles the sash. Does that make sense?

It's entirely possible your original coil balance springs were removed or lost in the past. That's not a big deal, we can easily suss out what you need. The 15-175 shoe is most commonly used with our Series 152 coil balance. While I can't be 110% sure that this is what you have without using the original as a reference, I still feel pretty confident that this will work for you. It's very unlikely that your window used anything else.

Now, you'll notice that the Series 152 has several weight options. To determine what you need, you simply get the weight of your sash and then divide that between how many springs will be used to support it. So let's say your sash weighs 20 pounds and you end up using 4 springs; you would want the S152-5, which carries 5 pounds each.

I highly recommend being as precise as possible when you get your sash weight. I've worked in this industry a long time and I've never seen anyone guess right. It's like counting jelly beans in a jar.

If your springs are missing then your spring retainers probably are, too. We recommend our 15-143 and 15-144 bushings, along with our 15-145 barrel. These sort of "sandwich"  over the spring and keep it stable in the track.

Please let me know if you have any questions!