Well i might have done almost the same mistake, mine was leaking some bits of coolant through the hole, I changed the seals ad lubricated with silicone spray so that they could mount smoother, but after a few kilometers it started to leak some bits again. I unmounted the pump again and cleaned the mechanical seal and the turbine white part with dish soap, mounted again and no leaks until now, (is was about a year and half ago). But I didn't grease the part where the mechanical seal sits, so if you check yours make sure that the mech seal is fully inserted, if it is, I think it shouldn't leak by there, but i'm not a mechanic