Which is the right coil mechanism?

Question

I have 2 windows that won't stay up. I think the coil mechanism is broken. I have no idea which parts and sizes that I need to fix it. I know that I definitely need the coils, but do I need the other parts too?

I figured out that they are MI Windows. The AAMA certification program information on the window is as follows:
Series: 8500
AAMA/NWWDA 101/I.S. 2-97
H-R20-48X78
H-R35*-36X64

Thanks!

Tom · Accepted Answer

If your other parts are in good condition, you can still reuse them. If you wanted to replace them anyway to be safe, then I recommend our 15-180 shoe, 15-186 clip, and 15-182 bushing. The coil spring would be our Series 190.