Great information Rip5 and very useful also. Must feel good knowing you fixed something and as a result, it's better than it was
The same scenario caused the lower rollers on our shower door to break off. On our first trip I had the black rubber strap/ring around both knobs to secure the door but a rough road apparently cause the retainer to let go, the doors to slide back and forth and damage to occur. When we got to our first campsite, one door was propped up on the bathroom floor leaning into the shower at the top. Didn't look good.
As previously reported, a call to Cruiser RV customer service (Dave) resulted in him sending me a complete new set of top and bottom rollers. They too, had been improved with metal areas that had previously been plastic on the originals (which had broken) so our doors slide smoothly and are much more robust now. They were quite easy to replace also. So I know the feeling
Also, as previously reported .... I now use a small bungee cord and wrap it around the knobs and then connect the ends together to secure the doors (as well as the original rubber strap).