Great work, congrats on getting it going. I don't know much about these pumps, but it's pretty amazing that the key is the weakest link. I know they are designed to shear, but that's still a bunch of force and I'm surprised there wasn't something else that would fail first.
Have fun with the cleaning. I spent the last 2 days cleaning mine and I'm still not done, but it's great to get rid of the gritty dust and sand. It's amazing the amount of dirt these trucks are carrying, I've got a 30ft long silty sandbar going across my driveway.