Our 5.0 pin box has holes in 4 different places. The photo below shows two of the holes on the left side. Identical holes are on the right side.
These holes allow water to enter, but it seems that the water does not drain and as a result the inside of the pin box is rusty.
Why are those holes there? It doesn't seem like a good idea to have them if they cause the inside of the pin box to get rusty.
Is it OK to plug/fill in these holes so that water does not enter the inside of the pin box?
We don't want to damage the pin box or cause any structural integrity, but also do not want rust inside the pin box