Step 1: Replace the Broken Tensioner

Use a utility knife to cut a seam in the plastic runner or sash guide. Unscrew any screws that are holding it in place. Remove the sash guide from place carefully; age can make them brittle.

Remove the window panel from the frame. Remove and replace the broken tensioner, which is located in the head jam of the window. Fasten the new tensioner in place with screws.

Step 2: Replace the Window Frame

Pull the tension cord until there is enough slack and insert the end into the window frame. Do the same for the other side of the window frame. An extra set of hands is helpful.

Place the window frame back in place. Be sure to line up the window track. To further seal and adhere the runner to the frame, apply a bead of caulk between the runner and the window frame.

Step 3: Lubricate the Sash Guide

To reduce noisy friction, rub the inside of the sash guide with a bar of soap. Silicone or baby powder will work as a lubricant, as well.