DougR is yr man, If he doesn't chime in you could PM him.
I doubt Volvo
makes the raw water
pumps but I dont know.
Suspect they will be Johnsons in which case you can buy seals
, bearings to fit frm a mechanical seal outfit or a bearing supply place.
I have rebuilt them but only on Yanmar
& Lister but when they quote me parts
prices I say you should be wearing a mask, cowboy hat & have a belt with 2 revolvers on.
Ok update that with hoodie, mask & Glock.
Anyway all seals & bearings have dimensions so measure them & try & source elsewhere if $$ are an issue.
Good questions you ask, try & source a wkshop manual as well.
I made my own ss exhaust elbow
as the Yanmar
one is a bad design & very expensive as yrs will be. Try exhaust elbow
or HDI marine
for ss alternatives bearing in mind I don't know yr engine