Your in luck, because I was stuck on the very same part just a few days ago. It sounds like you only forgot to do one thing...You already went into the top part and clawshooted the circular thing, and brough it down with your boots, however, you then need to drop down to the bottom part, but not to the floor. Drop down, then latch onto the gated ceiling. Then hang down inbetween the fan blades and clawshoot (while still hanging) onto another circular object. Put on your iron boots and this will turn on the final fan which will lead you to the boss room. This was one of my favorite boss fights!
Good luck, and rep is appreciated.