Michigan State Brakes Certification Practice Exam

The appropriate tool for checking rotor thickness variation is a micrometer. This instrument provides precise measurements necessary to determine the variation in the thickness of the brake rotors. Micrometers are designed to measure small distances with high accuracy, making them ideal for assessing the evenness of the rotor’s thickness. Ensuring uniform rotor thickness is crucial for optimal brake performance, as variations can lead to vibrations and compromised braking efficiency.

Other tools listed, such as caliper gauges, dial indicators, and feeler gauges, serve different purposes. While a caliper gauge can measure thickness, it doesn't provide the same level of precision for small variations as a micrometer does. A dial indicator is typically used for measuring displacement and can indicate runout or warping rather than thickness variation specifically. A feeler gauge is more suited for measuring gaps and clearances, not for accurately assessing rotor thickness. Thus, for the task of measuring rotor thickness variation, the micrometer stands out as the most suitable tool.