I heard a clanking when I was driving and determined it was from the right rear wheel. I took off the drum and think that the piece may go in the bottom where the gap is, highlighhted with the flashlight. What is this piece?

 

That is your brake adjuster.

 

Ok so what do i do now, and what happens if it isn't in there?

 

yea, that needs to be fixed. i dont mess with drums often, but if i remember right that brake wont work without it

 

Turn the slots on the ends vertical, and slide it between the metal parts of the brake shoes. It sets and adjusts the width between the bottom of the brake shoes. Without it, only the top part of the brake shoes will push against the drums. The serrated wheel presses against a plate behind it; this stops the adjuster from freewheeling. When you back up and hit your brakes it's supposed to ratchet it out to make sure the brakes wear evenly. Sorry, but it's been so long since I've worked with drum brakes I can't remember which way it goes in, but if it's put in backward it will turn it the wrong way until it gets short enough to fall out from between the shoes...I think that's probably what happened.

 

looking at the picture the brake adjustor that has the gear end should be on the left. hope that helps