New here. Had a leak in the toilet so thought it was only the flapper. Bought a new one. Then in the middle of the night the fill valve broke off, had water everywhere. Bought a new one. Then determined the flush valve assembly needed replacement too. The black rubber ring is very soft and small pieces came off in my hand. Finally got up enough nerve to take the tank off. Unscrewed the bolts and thet nuts came off in me hand. Went to pull the bolts and they will not come off. Don't understand at all. How do I get the bolts off, please?