Rectangular plastic sliders are breaking at top of door. I have 6 doors. Any replacement parts?

Rectangular plastic sliders are breaking at top of door. I have 6 doors. Any replacement parts?

I recognize this part. Stanley started with discontinuing this part and then later discontinued its replacement. We now offer our 23-196 roller assembly as the alternative.This actually comes with a wheel screw adjustment wheel and not the spring loaded guide wheel you may be used to seeing. Because of that, you may have to adjust the wheel a few times in order for the door to slide smoothly.