Holds top down bottom up window in place?

Hello,

Your pivot shoe resembles the 15-177, but you'll need to remove your shoe to confirm the specifications below match yours. It uses the Series 152 coil springs. See the related parts and videos as well. Thanks for posting! 

Alternate image for 15-177

There should be a cutout in the jamb for removing the hardware. If not, you'll need to make a cutout to slide the balance up and out of the opening. See the video below and related videos on this page to assist you.