Some toilet problems cannot be fixed, according to Toiletology 101. A cracked ceramic toilet tank and bowl are unrepairable. Water pressure, temperature and user weight can cause cracked ceramic porcelain to rupture. But, superficial cracks in the ceramic finish or a crack in a tank lid can be repaired with a rotary tool, a grinding bit, epoxy and meticulous care. Before making the repair, assess the depth, direction and location of any toilet crack.