I had this problem some years ago with a Wot 4 (high wing sports Type), never did find a cure but I wish I had, in the end the fittings got so loose I had to retire the model.

I would strongly recommend that you implement a 'fix' other than lubrication, remember that as the dowels are worn down, so the holes will be reamed out, simply replacing the dowels will not work long term.

Simon.