The glass panel is fixed onto the front bezel with fourteen magnets around its perimeter.
Stick two suction cups to opposing corners of the glass panel.
To attach the suction cups we sell, first position the suction cup with the movable handle parallel to the face of the glass panel. While lightly holding the suction cup against the glass, raise the movable handle until it is parallel with the other handle.
If your suction cups refuse to stick, try cleaning both the glass panel and the suction cup with a mild solvent.
Gently pull the glass panel straight up off the iMac.
The glass panel has several positioning pins around its perimeter. To avoid shearing these pins off the glass panel, be sure to only pull straight up during removal.
Be meticulous about cleaning the LCD and the inside face of the glass panel before reinstallation, as any fingerprints or dust trapped inside will be annoyingly visible when the display is on.
When replacing the glass, be sure there's nothing between the glass and the frame. Stray cables could be damaged or crack the glass.
Remove the following 12 screws securing the front bezel to the rear case:
Eight 13 mm T8 Torx.
Four 25 mm T8 Torx.
On the 24" iMac Intel Model A1225, the bottom center two screws are long (26mm), four on sides (two left, two right) are medium (18mm), and the remaining 6 (four top, two bottom corners) are short (14mm).
While still holding the display panel up, use two fingers to firmly push down on the power supply cable connector from its socket.
Be very careful not to touch the exposed face of the power supply to avoid electric shock from the many large capacitors attached to the other side of the board.
To remove the optical drive thermal sensor, use the tip of a spudger to lift the center finger of the thermal sensor bracket while applying slight tension to the thermal sensor cable.
If the thermal sensor is stuck to the optical drive, skip to the next step.
Use the flat end of a spudger to pry the optical drive thermal sensor bracket up off the adhesive securing it to the optical drive.
If the adhesive gets dirty or will not stick to your new optical drive, place some double-sided tape under the two semicircular ears of the thermal sensor bracket.