Leaving original adhesive or other foreign material on the display glass or chassis may result in a poor bond, causing the glass to disconnect from the chassis.
Remove any adhesive residue or other foreign material from the display glass and chassis before re-assembling the iMac.
Avoid adjusting the screen during re-assembly. Adjusting the screen during re-assembly may result in a poor bond, causing the glass to disconnect from the chassis.
Allow adhesive to cure for 20 minutes before standing the iMac upright.