Many bearings are 'standard' items available from bearing supply houses.
If not by application or part number on the bearing then by dimension.

The problem is that you are likely to need to remove the bearing and take it to a bearing supplier for them to match or measure.

It might be worth just pulling up the pump, installing a new pump, and THEN seeing if repairing the old one is practical.
You then just keep it as a 'spare' waiting for the new one to fail.