How to Replace the Block and Tackle in Single-Hung Windows

Lift up on the sash clips that are located on the inside track of the window frame. These clips are rectangular in shape and are positioned just above the lower half of the window when it is closed. Use your fingernail to lift the bottom part of the clip up away from the frame.

Unlock the bottom part of the window and slide it up on the frame. When you reach the clips, push the window to one side and lift up. Remove the window from the frame to expose the balance.

Grasp the top and bottom ends of the balance using two hands. Pull outward on the bottom part of the balance gently and pull downward to remove it. Lift the balance approximately halfway up the window frame, and locate the hook at the end of the balance string under the balance.

Pull the balance string out of the hole to remove the balance. Repeat this process for the opposite side of the window frame.

Attach the hook of the new balance back into the hole by hooking the end into the hole.

Pull down firmly on the balance and lock the top of the balance into the sash clip by pulling the balance a half an inch below the clip and allowing it to move upward with the force of the spring. Let go of the balance so it sits in place in the frame. Repeat this process for the other side of the window.

Place the window back into the frame by pushing one side into the frame and pressing the other side into place approximately halfway up the window. Slide the window down until you feel the balance catch or you detect slight resistance.

Press the sash clips back level with the window frame.