I did one last year, completely seized. Popped it open and it was jammed full of heavy caked corrosion, no wiggle room at all. I vacuumed it out, submerged the entire unit in cleaning vinegar for 24 hours (smells nasty, and it burps and bubbles constantly) When it came out, I rinsed it well, greased the top ends up, put it back together, capped the bottom inlet, and put a quart of ATF fluid in it. That pump works so well I still can't believe it, and it's a joy to let people take the handle and crank on it, makes them smile. Try it, you'll be amazed, and it's fast & cheap!