Window won't stay up. Plastic piece stuck and other piece broke.

Hi there!

It looks like you have an old Simonton coil balance. We don't carry this exact system but you can replace it with our 15-259 pivot shoe and Series 159 coil springs. Take a look at the video below. This will walk you through the entire replacement process and the other parts you'll need for this repair. 

There should be a number stamped on the original coil that indicates the strength option. If not, you'll need to remove and weigh your window sash. Then, you'll divide the weight by the number of coils on both sides of the window to determine the correct strength option. If you're still unsure, give me the exact sash weight and I can work out what you need from there. 

You could try the 15-192 but you'd need to file down the "nubs" on its face and the overall thickness may also need need to be reduced for it to even fit in the track. Even then, it may not work. Your old shoe just isn't made anymore, unfortunately.