Now that we've had our fun, you might try looking at Mainsail's web site. He has lots of tutorials covering this sort of thing in detail.
But really, Boatman's post does tell it all... replacing seals
is pretty straight forward on all the Jabsco
pumps that I've worked on.
Hint: don't buy the replacement seals
from Jabsco. Get the old ones out and take them to your neighborhood bearing and seal shop. They will have the very same seals at a much lower price
. Buy some extra ones while you are there, both for future replacement when required and just in case you bugger one up installing it.