Aluminum Sash Guide

I'm afraid I have not been able to find a metal top sash guide that could substitute the 18-166. Are your current top sash guides breaking? Sometimes this is simply caused by age, especially if the top sash guide is exposed to direct sunlight. There isn't much you can do about that. It is also possible that your balances are getting stiff from age, which makes it harder to open and close the window. This puts excess strain on the top sash guide. Try lubricating the springs on your balances, that could help the problem.