Best fix I know is to replace it with the all metal one Stein sells.
I suspect it is not repairable, but you can most likely find an unused one from someone who used a Stein unit during their build.
Has anyone come up with a good fix for the adjustment flap in the plastic eyeball vents? It is difficult to get the darn thing to stay in one place.
Ed
Rotate the ball around and look for a small screw....and tighten.