I used a low-tech solution. I cut a shim out of a plastic milk jug and slipped behind the little wooden block inside.

Absolutely no lacquers, f.i. nailpolish stuff has prety nasty solvents ... wax the axle a little, or use something removable like rubber band, a plastic collar made from an old ballpoint pen or clothes pin below the stop to keep it up ... Nout

Thanks everyone.