Thanks Hillrider. When I tried to pry the cap off, it became obvious that it was part of the axle. A few taps with a hammer on the inside end pushed the axle through. Now the bearings still can't be gotten to. There's a 1/2" tube on both ends of the hub, that are free to turn but don't appear to be removeable.
At this point, I might just pack grease in the 1/16" space between the inner hub and the rotating end tubes.