In this keyboard key installation guide, we’ll show you how to install a type K31 replacement keyboard key. This hinge type is used in the Apple MacBook PRO UNIBODY.
The first step is to hook the wide slot on the hinge over the metal bar on right of the empty space on the keyboard. Take the hinge and open it up. Hook that slot over the metal bar. Then use some pliers or your fingers to push down on the left two corners of the hinge until it snaps on. Set the rubber spring in the center. Then take the key and set it on top. Push down on it, snap it on, and then you’re done!
The colors in the video may differ for your model, or the hinge may be rotated from what you see in this video. That’s fine, what matters most is the shape of the hinge piece.