Tap the plastic outer hub casing firmly to knock it off; or pinch it off with pliers to reveal the slotted metal disc holding the wheel onto the axle. Insert a flat screwdriver between the disc and the wheel hub. Pry the screwdriver away from the hub and bend the disc outward. Tap bent disc with a hammer to loosen flanges around axle. Slide off the disc. To see how to attach new hubcaps go to
assemble the wheels page. Or just tap the new hubcap on with a hammer. NOTE: the axle must enter each hubcap to same depth or the wheels are not secure.
