If I had that unit, I would take a wrench (or socket) and remove the bolt. With a little help the stand-ends should pull away from the wheel/tube assembly.
Should then be easy to see if it's a sleeve bearing (use some wheel bearing grease) or a ball/roller bearing. For the latter you may be able to push in some grease and maybe not - depends on the style. And if the bearing is screwed up your best bet might be a local well-equipped Hardware store.