Replacement "wiper" o-ring on a D4D track adjuster

While repairing a leaking track adjuster, noticed the o-ring that is supposed to be serving as a wiper is floating along the exposed chrome cylinder of the adjuster. The rather thin metal lip that held it has corroded into oblivion. Looking for ways to retain the original o-ring via a fabricated metal ring retained by drive screws as well as some sort of replacement, like a repurposed lip seal.

Replacement "wiper" o-ring on a D4D track adjuster