As Gerry said, try tightening up the for screws that secure the hinges to the bottom half. There are two on the rear where the ports are and two on the bottom, they should have a D next to them. If it's still a bit loose peel off the screen bumpers on the lower left and right corners of the screen and tighten those screws down as well. The gum on the bumpers should hold up where you can stick them back on. They did on my D820.
And if you do use Loctite, use the BLUE not the red. The red is semi-permanent and will make the screws impossible to remove. I replaced the original screws on my D820 with some 440 Stainless Steel ones. They're super hard and you can tighten the bejezuz out of them. They haven't come loose AT ALL.