G'day Trevor.
The topic went a little sideways. Its not the pump but the sump where the problem is. A stud hole for the sump plate.
Cheers
I will claim old age .
On a sump plate hole, 50/50.
Lumiweld should hold if you can get the cases clean enough.
I would still go with a weld.
Or even an alloy plug peened so it can nor screw itself out then drill & tap a new hole for the stud.