Seat bolting parts are new/different
This Aquia II is matched to an SS04 soft close seat (this is the pairing suggested on the TOTO web site). The pad between the hinge case and the bowl is white flexible vinyl (their parts list calls this the "rubber seat stopper"). Now here is where it gets confusing. The toilet install manual, AND the seat install manual both reference top-mount, flat head, slotted plastic bolts that use cone washers and plastic nuts. What I got with the toilet was very different: two long phillips round head stainless bolts and metal washers and two 3 inch black rubber inserts with thin rubber flanges at one end. You insert the rubber tube into the hole on the bowl until flange is flush with bowl, then put hinge case over that, then the bolts with washers. You tighten for many many many turns to get the rubber inserts to compress. I have re-tightened these, thinking maybe I just didn't get this tight enough. Either that, or the squeaks are inherent given that there is plastic rubbing against plastic in the way the hinge, hinge case, and seat fit together. Any thoughts on this bolting technology, and whether the plastic bolts might solve this?