Water compartment in gear housing under waterpump faceplate get corroded on my Alpha One Gen 2. Especially thin wall outside pump (red arrow).
My gear housing looks like:
It is not perforated yet, but wall thickness on the top in some spots as thin as 1mm vs original 3.2 mm.
Also, it was already patched previously by someone with some kind of compound on front left corner.
I have rubber filler plug installed on other side of this wall. Probably older aluminum dam would be better since it will
work as sacrificial anode. Also, I had bad habit leaving drive up during summer storage, trapped water in there might worsen corrosion as well.
Leaving it as it is now will cause perforation and water pump failure in couple of years.
What would be the best way to repair it?

My gear housing looks like:




It is not perforated yet, but wall thickness on the top in some spots as thin as 1mm vs original 3.2 mm.
Also, it was already patched previously by someone with some kind of compound on front left corner.
I have rubber filler plug installed on other side of this wall. Probably older aluminum dam would be better since it will
work as sacrificial anode. Also, I had bad habit leaving drive up during summer storage, trapped water in there might worsen corrosion as well.
Leaving it as it is now will cause perforation and water pump failure in couple of years.
What would be the best way to repair it?