I have a 4045HF285 that needs a water pump. Inspecting it I found a question. Right in the center of this picture there is a hard line that goes up from the pump, through a strap with 1 bolt, to parts unknown. The pictures of replacement pumps I have found just show some kind of hole where this hard line goes in, but not enough detail to see what seals the hard line or how it removes or installs.
It is a metal sleeve with a rubber insert. R123226
Pry the old seals out with a large, flat blade screwdriver. Tap new ones in lightly with a soft hammer or hammer and wood block. I like to lube & seal the outside of the seal with RTV sealant. The steel pipe just pushes into the seal section. A little vaseline on the inner side of the seal and/or metal pipe will set it home easier.
All of those water pumps I have replaced came with that seal already installed. It is not necessary to remove that hard line, just remove the strap bolt and pull the water pump down out of the pipe. There is also a thin metal plate that is. Called an insert. This has a sealant that comes with the insert that goes between it and the front cover gasket goes between the water pump and the insert Insert 17