Any IH 800 planter experts on the OB?

I have an old planter that I’m trying to troubleshoot and can’t really find much info searching the web. Any recs?

I use the planter in a no-till fashion. It cuts the soil and deposits seeds perfectly, with good depth control. But the closing wheels don’t seem to be doing anything. The trench stays open much of the time. I’d thought that the wheels may be worn, but they don’t seem to be.