Constant flexing can wear out the rubber pieces that connect the treadle to the rocker on a Lendrum folding wheel. This replacement connector is easily installed: unscrew the screws holding the old connector in place, remove the old connector, slip in the new one, and tighten the screws in place.
The single treadle Lendrum wheel uses the short (5") connector.
The double treadle Lendrum wheel uses one each of the 5" and 7" connectors. The 5" connector joins the left treadle to the rocker; the 7" connector joins the right treadle to the footman, through the rocker. They are sold as a pair.