The round bar that's about 5/8" or so in diameter is part of the seat frame and is not removeable. There is also a flat metal piece about 7 or 8 mm wide, and slightly longer the the width of the seat frame, that slips through the front flap of the seat material. The ends of this flat metal piece fit through small holes on either side of the seat frame and pull the seat material slightly taut. This flat metal piece is located very closely to the larger round bar, and unless you've seen them apart, it's easy to think that they are connected. There should be one or two spring metal "clips" that encircle the seat material and fit around the larger round bar. These clips are about the same diameter as the larger round bar and abount 10mm wide; they have "pointed ends" that grip the seat material making the clips a little difficult to remove without tearing the material. Once the clip(s) are removed from around the seat material and larger round bar, the flat metal piece can be pulled or "bowed" outward until one of the ends releases from the seat frame. At that point the front of the cushion is free. The rear attachment is very similar. Some seat cushions have "s" clips about mid way between the front and back. If present, these clips must be unhooked to remove the seat cushion. If I recall correctly, with the seat in the car, these "s" clips are tough to get to. Good luck!!