Thanks Shandy!

It looks like Zade was able to replace vacuum elements ("billows") without going any further on the cabin side than I already have, though I'm not sure that would be true for all of the elements that are in the car (my vacuum tests indicate problems with the Fresh Air and Defroster elements, and/or their lines.) Without the new parts in hand, I can't visualize how to get the old ones off.

I removed the lines from their individual "L connectors" by heating them with a hair drier, but I'm beginning to think that may cause problems when I try to get them back on. Oh well.

Steve