Changing a Fan Belt

[chesapeake bill]

My water pump had to be replaced so got a new one and a fan belt. I moved the Radiator forward to remove and replace it. Now I can't get the belt around the bottom pulley (crankcase pulley) there seems to be something under the pulley that is keeping the belt from sliding on. Any ideas how to get this belt on? Is there something like a guard or bolt below the pulley? Need help on getting this thing back together. Thanks