As you can see from this picture, part of my Derailleur is loose. Notice how the gear is not in flush with the cylinder.
It has a no other parts (that I can find!) than a threaded screw to go in there, but the screw bottoms out or at least seems to before it pulls the assembly in tight.
The screw itself is not of such diameter that it would hold the device in place, and while the geared part is secured by a metal lip on the side of the gear when you push it in place... the screw doesn't do the job.
This is my first time working Derailleur system. I have no idea what part I'm missing. I'd appreciate anybody who could tell me what it is I need..
Oh, and for the record. This is the image of what the thing hooks onto.