The front left screw for my KONI strut (the small one that holds the koni strut to the insert, at the bottom) came out and I really need to know the size of the screw so I can buy one from home depot or something. If anyone knows the length and diamter of the screw that will be appreciated.

Plus, does anyone have any idea why it came out? Am I missing a washer?

Did you put a little threadlock on it when you put it in? I put some of the blue stuff on, and then make sure it's properly torqued.