I haven't used this strategy on this tricycle, but have you tried using a rubber "O" ring placed at the handle bar's joint? If you go to a hardware store with the handle bars, or the measurement of the diameter of the male side of the connection, they can help you find the correct rubber "O" ring to use. Just slide the "O" ring over the male connector and tighten the handle bars down as you would without the "O" ring in position. This should prevent the handle bars from slipping out of place. I hope this helps.