Originally Posted by
n plus one
Remove cover, turn filter to remove, fill new filter with clean diesel, push upwards and turn, reinstall cover, crank engine over.
Or did you mean pump? It doesn't look too bad to me (famous last words) but you'll need to be able to do a pilot and injector learn?
Do you have any info that's leading you to replacing the pump (rail pressures, etc)? Or just looking for a possible first step (and assuming that lack of lubricious has flogged the pump)?
Try draining a few fuel samples and looking for 'glitter' with a torch - if you find it suspended in the fuel it'll likely be metal wear from the fuel system and you're probably in trouble.