Bicycle Mechanics - Stupid question from a silly guy

Alright, I need some help. It's elementary as anything, but I just can't figure it out. Anyone could probably answer it, just not me.

While cleaning my bike, I thought I'd adjust the height of my handle bars and bring them up. So I loosened the bolt on the stem (I guess that's it.) and twisted it up to the right height. Then I tried to tigten it back up, and darn, it wouldn't tighten back down. When I turn the alen key, it just spins and spins and spins.
I didn't mess with the headset or anything, just the stem bolt.

Right, thanks, and I await your help.

I've got a totally stock Trek 3500

You probably loosened it too much and dis-engaged the wedge type thing that holds the stem in place.

try pulling your stem all the way out, flip the bike over and the wedge thing will fall out (might require some jiggiling) then re thread it through your stem bolt and set to the right hight and tigten.

Good Luck

Ray

Thanks mate. Easy piesie. This is why this forum is so great.

If by chance Lambs advice is not the problem, then try taking your allen key put it on the stem bolt and hit the key with your palm which should make the bolt drop slightly, when that happens try tightening it again. Word of caution, do not over tighten those bolts because it could damage your head tube.

If you fail to shake the wedge loose take the bolt and try to thread it into the wedge and use the bolt to draw the wedge up and out.