Properly repair PS2 slim rear lid sensor

[dbeamer407]

My 12 year old son has a PS2 slim and has really been getting into Castlevania lately and he is excited to play Symphony of the Night on it. However the rear sensor is failing. I can get the disc to spin by pressing down on the lid above the sensor. I would like to repair this for him. There are lots of webpages that suggest jamming some foil in that area to press the sensor down. Is there a more proper way to make this repair? I understand the principle of the problem but have not opened the console yet to see the details. It just seems that jamming a ball of foil inside is probably not the best way to repair this!