Which describes a shielded bearing when over-lubrication leads to failure?

• A. Collasped shield
• B. Collapsed shield
• C. Collapsing shield
• D. Collapse shield

Answer: (A)

Shielded bearings rely on a barrier that keeps lubricant in and contaminants out. When you over-lubricate, the excess grease and the heat it generates raise the internal pressure inside the bearing. That pressure can deform the shield inward, causing it to collapse. Once the shield collapses, the seal between the bearing parts is compromised, lubricant can leak out, and dirt can get in, leading to accelerated wear and failure.

The phrasing that matches this failure mode is a shield that has collapsed. Other options imply the shield is in the process of collapsing or use awkward or incorrect wording, but they don’t describe the final, damaged state as accurately as the term where the shield is collapsed due to the over-lubrication pressure.