Just a word of caution for you info.
This is one time I would recommend using the Volvo genuine part. There is a small stainless steel spring inside the seal that retains the inner seal face pressure on the shaft. It is not visible unless you dig round in the seal. Its tucked under the lip. The genuine part should have the spring made of SS, it still corrodes away due to crevice corrosion eventually (if the engine is not run regularly)but, I have seen non genuine automotive parts used where the spring is steel and can rot out in a few weeks.
It then rattles around behind the impeller doing more damage and can even end up in the heat exchanger along with the bits of broken impeller from over the years
We actually have a spare pump for or D1-30 it was a "gift" shall we say
Its ready to swap out every time we do an impeller change or the seals fail... As they do. I can change the whole pump quicker that I can any of the components.
When you replace the seal use glycerin as a lubricant as you would replacing the impeller this will help the seal slide over the shaft as its fitted and prevent damage. When the water goes through the it will wash away.
Hope this is of use.
Ant.