I am looking at the pictures and I am thinking that what is on the shaft and goes through the bearing is actually what is holding the Pump in.

If some member has a free online sight you can look at so you can see the Factory Service Manual I think you might fid you need some sort of puller to pull it straight off.

These are generic methods that I have used over the years on other things:
If it was only the flange and adhesive holding it on I would say heat it with a propane torch or a hand held butane torch to soften the adhesive. It should not take much heat to do that.

The other method is a little more tricky on parts with aluminum castings and thin flanges which is to get a knife that you can sacrifice and get the blade between the parts and tap it in a bit then go to the opposite side and do the same and all around it if you can get to that. However, it is going to be very subjective as to how much is too much.

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84 300D, 82 Volvo 244Gl Diesel