Some progress. I managed to remove the wiper and the seal underneath
it. However, I'm a little confused as the new seal doesn't look
exactly like the old seal. The old seal is shaped like and inverted
U. It sits on top of a brass ring that has a tongue that can fit up
into the U. The new seal is identical, except that there is an O-ring
in the U. If I remove the O-ring then it looks just like the old
one. I can certainly do that, but I wonder about it. Maybe the O-
ring is just to keep the seal in shape while it sits on the shelf?