I have recent experence with M602 water pumps. They come off the engine easily by removing hoses and 5 studs to remove from engine. The hard part is the book says "Support tractor under engine and unbolt and slide radiator,front support and axle assembly forward.
The pump comes apart easy by unbolting back cover and removing collar on the shaft by driving roll pin out. Taking rotor off shaft would require a press and I don't know if or where you can buy that part.Maybe the kit comes with a rotor???
What I found you could buy a pump kit from a old MM service place(Agco parts) for $160.00-$170.00 or a completely rebuilt one for about the same amount ($170.00) I think the kit had a pump seal,bushing and a oil seal which I found some parts at McMaster-Carr supply that was the same for a total of $22.75 plus shipping. I rebuilt 2 pumps for way less than a new-rebuild one but did not need a new rotor.