spiral balance for tilt window

Our buildings have reynolds aluminum windows which were manufactured in the early 80's, series 6100. The sash weighs 40 lbs. Siral balance length is 31", diameter 9/16". Which spiral balnce do I need and what is the price?

The balances I now have all seem to have the same problem, the spiral rod with the tilt pins on it, which is inside the balance, disconnects and pulls out of the balance.

Tom

The windows are single hung tilt windows.

Sorry that I do not have a picture of the tilt pins. But it is not the tilt pins that are the issue but rather the spiral rod itself from inside the spiral balance that becomes disconnected and pulled down and out of the spiral balance. Thus the spiral balance becomes ineffective. The rod remains connected to the tilt shoe.

Fr Tom