Automobile & Light Truck Certification Test A5 BrakesDrum Brake Diagnosis and RepairMedium
A technician is performing a rear drum brake adjustment. The vehicle has non-self-adjusting drum brakes. After replacing the shoes, the technician needs to set the initial shoe-to-drum clearance. The manufacturer specifies a clearance of 0.006 inches. Which of the following tools is BEST suited for accurately measuring this small clearance?
- AA measuring tape
- BA dial caliper
- CA feeler gauge
- DA micrometer
Show answer & explanationAnswer & explanation
Correct answer: C. A feeler gauge
A feeler gauge is specifically designed to measure small gaps or clearances between two surfaces, making it the ideal tool for accurately setting the precise shoe-to-drum clearance of 0.006 inches.
Why the other options are wrong
- A. A measuring tape is for larger, less precise measurements.
- B. A dial caliper measures dimensions, but is not ideal for measuring fixed clearances like a feeler gauge.
- D. A micrometer measures external or internal dimensions, not clearances between installed parts.
Feeler Gauge
A tool consisting of a set of blades of various calibrated thicknesses, used to measure small gaps or clearances between components.
- Measures small clearances.
- Blades are precisely sized.
- Used for non-self-adjusting brakes.
Memory trick: For a tiny gap, a feeler's lap, precise and no trap.