Comparing your axle to mine, the fin thing on yours does not appear to be fully seated on the axle. I wonder if there is any way to pull or pry it on the rest of the way.
Uhhhh! Drove it around some more and the squeaking came back. I saw some other threads about the same issue. They changed thier brakes pads and made sure everything was well lubricated with the appropriate brake lubes and it seemed to have worked.
You said you can spin the axle and hear the squeak. You should be able to determine if it is coming from the fin or the brakes. I'd do that before spending time and effort on things that aren't it..
You said you can spin the axle and hear the squeak. You should be able to tell if it is coming from the fin or the brakes. I mentioned the gap I see with the fin because it might make it rub; I don't know how much clearance it has behind it.
I went ahead and decided to clean the brakes with brake cleaner. As of today the squeak is gone. We we will see how long it goes before it starts up again.