What happens when the brake pedal is pressed for drum brakes?
- The shoes pull inward, away from the drum
- The drum expands to meet the shoes
- The drum rotates faster to create more friction
- The brake shoes push outward against the inner surface of the drum ✓
Answer: D. The brake shoes push outward against the inner surface of the drum
When the brake pedal is pressed in a drum brake, the brake shoes push outward and press against the inside surface of the drum.
Why this is the answer
The handbook describes drum brakes as having brake shoes and linings inside the drum. It says that pressing the brake pedal makes the brake shoes press outward against the drum surface. The inspection section also notes that the lining must press against the drum for the brakes to work. So the action that produces braking is the shoes moving outward into contact with the drum, not the drum changing shape or the shoes pulling away.
Why the other answers are wrong
- A. The shoes pull inward, away from the drum — The shoes do not pull inward away from the drum when the brakes are applied; being out of contact with the drum is what happens when the brakes are released.
- B. The drum expands to meet the shoes — The drum does not expand to meet the shoes; the handbook says the brake shoes are the parts that press outward against the drum.
- C. The drum rotates faster to create more friction — The drum does not spin faster to create friction; pressing the pedal applies the brake shoes against the drum surface.
Remember it
Picture the shoes inside the drum stepping outward to grip the inside wall.