Air Brake Coach
Brake adjustmentQuestion 56 of 116

What does an s-cam do when the brake applies?

  1. It releases air from the chamber
  2. It turns the wheel
  3. It pushes the brake shoes against the drum
  4. It pulls the shoes away from the drum
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Correct answer: It pushes the brake shoes against the drum

The cam lobes expand the brake shoe platforms. The lining then presses into the drum.

Source: Air Brake Manual: A Guide for Instructors (Government of Alberta, Alberta Transportation, March/April 2012), Module 8: Foundation brakes, page 76

Practice brake adjustment

Questions last reviewed: 18 October 2026