Home window wood circa 1967 Chicago suburb Hanover Park

Aloha,

Refurbing uncles house. On this window, it has a spring assist mechanism within an aluminum frame on each side. The bottom hook of the spring on the left side (from interior) failed. We need a new spring?.which is off site. The spring is about as long as a small water bottle terminating into a hook on each side. We bent some tabs and opened the casing to reveal a block and tackle pulley system attached to a strong spring. We require another spring and possibly new Paully (block). Hopefully y'all are window ninjas and this is old hat?.fingers crossed. Appreciate your time and consideration.

Aloha,
Dave