I personally don't think that piece will just come off for an easy replacement. Those are held by metal pins. Which I think have to be heated with a soldering iron at a low temp to gradually soften the surrounding plastic then pulled away gently. I'm not sure, however, if it will go back to it's original state after the repair has been made. On the other note, that part of the design transformation is a swivel point and does not require a ball joint for many reasons. The only true issue is the plastic that was used, it might be cheaper plastic. I honestly don't think that is an ABS part since it should have a higher break tolerance. Lego bricks are made of ABS. Think about how much play-wear they go through, being connected, pulled apart, bit, stepped on, etc.