I installed a Toto Drake two piece toilet and have had a slow leak for a few weeks now (off and on) from one of the bolts which attach the tank to bowl. I tightened to the point I thought was as tight as I could without cracking the tank. I also tried disassembling and reassembling the two parts. Same result. Could the leak be from the main connection from tank to bowl and then leaking out the bolt (the rubber gasket not working?) or is it simply the bolt should be tighter. How do you know when it is tight enough? Any advice??????? I never installed a toilet before and seemed to be easy enough..just that darn slow drip.