Secondary plates

Is ti the shaft sticking or the secondary plates sticking?If its the plates,try taping with a plastic rod to just see if it will losen the bores,I would then try any chemical that could help reduce the corrosion in the shaft,and after cleaning the base,try very carefully a litte heat to casting around the shaft,and be carefull,to not over heat the surface and do it on both sides and cool it with penatrating fluid,Mrmopartech