What will result if brake drums are worn thin or turned too far?

If brake drums are worn thin or turned too far, they may become structurally compromised, leading to a reduction in braking efficiency and increased stopping distances. This can cause excessive heat buildup, resulting in brake fade and potential failure. Additionally, worn drums can lead to uneven wear on brake shoes, causing vibrations and noise during braking. Ultimately, it poses a significant safety risk for the vehicle.