A folding device for placing an elastomer thin sleeve on a retainer includes a mandrel, one or more rollers, and a drive system. The mandrel is configured to translate relative to a portion of the folding device. The mandrel is adapted to releasably receive the retainer. The one or more rollers are configured to rotate relative to the mandrel. The rotation of the one or more rollers being configured to fold the sleeve onto the retainer. The drive system is configured to translate the mandrel and turn the one or more rollers.