So you have a crack in your pin block... so what? Does it still play okay? Does it hold tune? You might have a tough time selling it, but it could still serve you well for many years.
I moved my grand from a balmy coastal climate at sea level to northern interior Canada at 1500m. Very dry and cold. Cracks developed in the sound board, which was very disturbing, but it still played and sounded fine. A few years later we moved back to the south coast, and within a couple months the cracks closed back up!
I know a soundboard and a pin block are different animals, but it still makes for an interesting story.