Two of my toilets were running, so I bought some devices to replace the innards of the tank. But I cant figure out how to remove them. I got one piece removed, but the column in the middle is still in there. I think I need to remove the top part of the tank with the bolts there. but I cant make them budge. How do I remove that, and do I need to be careful about resealing it with tape or goop or anything else? There must be a how-to on the internet somewhere.