Larry, I think that the Mark 6 may be different in that the lower seal
goes into the water inlet cap instead of the block itself.
Anyway, here’s the inside with the "cap" removed.
As said, the job can be done with the pivot tube left on,
but you have to get creative with tools to scrape
the cap gasket surface, remove the cap screws, install
the seal, etc.
Attachments:
Prepare to be boarded!