[Richard L]

The most probable place for the water entering the pump is at the cable gland. If you put some silicon sealant around that area, it will help a great deal.

Are you replacement the older pump with a aquamist pump or from a third party supplier. All non-aquamist pumps run at a slower speed, higher cam profile and very strong bypass valve spring. It makes the line pressure very spiky and draws very high currents. It you adjust the pressure down, the pressure spike gets bigger.