To paraphrase James Carville, "It's the SPRING, stupid!" Although I just discovered this on my own, I see in comments above that Matt Newland, 2/27/15, had already suggested this. To further explain: my wife in cleaning the pot had taken the spring off and, I discovered, replaced it upside down - with the wide end facing down. The wide end needs to be facing UP. When assembled, this then puts pressure on both the bottom of the percolating tube so ALL the hot bubbling water flows up the tube and on the coffee grounds container to seal it against the cover so that all of the up-flowing hot water flows across the container and not by-passing it over its sides.
My wife was thrilled (well maybe that's a little strong) with my genius, but then wondered how many coffee pots she had unnecessarily replaced for her 100+ year old father.