This article explains about what can cause this and has a follow up on how to.
View Snowblower Sheer Pin Pics. Replace the cheap shear pins with hardened unbreakable bolts and you'll defeat the purpose; A forum community dedicated to snowblower owners and enthusiasts.
Old bill finally bought a snowblower. I found some ariens bolts that were similar to my bolens snowblower from a guy on the web. A wide variety of shear pin options are available to you, such as theory, usage, and material.
But you'll learn an expensive lesson.
It is designed to break away in case foreign objects come in contact. Just throw a couple craftsman snowblower shear pins in your pocket before you head out to clear the driveway and know that no matter what lurks under the snow, you've got it. Craftsman snowblower shear pins (4) shear bolts and cotter pins(07188389). Shears pins (bolts) are $1.50 each if you can find them.