try taking old the main bolts you can see from the outside of it then get one to lift the bar up while another uses a hammer and punch and knock the pin that holds it all together downwards
buuuut there is more under the bar that you can remove afterwards to get more weight off
put some lubricant through the hole where the phillips head is and use one of those phillips head end punchs on it that loosens it every hammer hit
Also, get someone to hold the bar whilst you try and undo it cos once the bar is unlatched its putting pressure on that bolt