Replacement tank arrives
Was able to find a new Washer Tank (lower reservoir) in the 40 dollar range which wasn't bad at all. It's older looking than the original in the Riv, and a different part number! At least the rubber bumper is already in place (saves a step.)
Washer fluid being drained from the broken unit.
How outrageous!!
Tank removed
The hose and cable shield were cleaned-up, fed back into the engine compartment and tie-wrapped to hold them in place temporarily.
Problem with mounting arrangement
I believe the tank mounting scheme is a bad design. Looking at the capture-nut, it's not flush with the inner fender surface. It's "raised" and presents a very small area on which the plastic 'tab' of the tank sits. This could be the failure mode.
A close-up view of the mounting nut. I'll be looking for some RUBBER or a rubber washer to 'beef-up' or provide extra support/contact area.
It's a fun project.. and a challenge all right.
-Ed