Fixing Roomba 500/570 side brushes with stitches
The Roomba 500 series side brush is infamous for amputating itself. Over time, the arms of the side brush weaken and break off very near the center hub. It's very hard to glue the arms back on since the surface area of the breakge point is very small but it looks like you could simple stich the arm back on using a small needle and thread.
Here's some pictures of a side brush with an arm reattached using stitches!
The side brush was first attached back to the hub with some superglue and left to dry for 15 minutes (aparently superglue can react with cotton and catch fire!). After the glue dried sufficiently, I used a small needle and thread and stitched the arm to the central hub. I didn't make too many stitches as I was concerned that too many needle holes would compromise the plastic.