Final answer:
An indicator of contaminated brake shoes can be reduced stopping power. Other potential indicators include excessive wear and uneven drum surface.
Step-by-step explanation:
An indicator of contaminated brake shoes can be reduced stopping power. When brake shoes become contaminated with oil, grease, or other substances, it can reduce their ability to generate friction against the brake drum, resulting in less effective braking.
Other potential indicators of contaminated brake shoes include excessive wear and uneven drum surface. When brake shoes are contaminated, they can wear out more quickly, and the brake drum may develop an uneven surface due to reduced friction.
One common cause of contaminated brake shoes is leaking brake fluid, which can contaminate the braking system and impair its performance.