Itasca uses Sealand toilets, which are quite easy to maintain.
Leakdown is caused by an accmulation of lime scale on the teflon seals. You may be able to dissolve the lime by pouring in a few cups of vinegar, and then working the valve after the vinegar has leaked out, to dislodge any lime residue.
For really stubborn stuff, or a maintenance operation, you lift the top half of the toilet off, providing you with acess to the teflon seals, which just lift out for cleaning.
Removing the top half of the toilet only requires removal of two screws: The one that holds the plastic shroud around the toilet; and the screw which secures the clamp which holds the upper and lower part of the toilet together.