Please help me, I have a toilet that seems to have a mind of its own. When I go to flush it, the noise happens, the tank drains, but the water raises in the bowl. I have tried to plunger it as well as poor bleach down it. I have also tried to find a diagram on the net and have had no luck due to the age and not knowing what brand it is. If you have any ideas please tell me, I will be most grateful.