Practice question

What does the S-cam do in an S-cam drum brake?

  1. It releases air from the lines
  2. It rotates between the brake shoes, forcing them outward against the drum
  3. It cools the brake drum
  4. It activates the low-pressure warning

Answer: B — It rotates between the brake shoes, forcing them outward against the drum

The correct answer is shown above. Try the full quiz for additional practice.

Practice more: Arkansas CDL Air Brakes Test Practice Questions - Arkansas Commercial Driver License (CDL) Air Brakes Knowledge Test Exam →