Final answer:
Improper application of brake shoes can be caused by worn brake shoes, contaminated brake fluid, and faulty brake calipers (or wheel cylinders in drum brake systems). Therefore, all of the factors listed can contribute to inadequate brake function.
Step-by-step explanation:
The question regards what can cause improper application of brake shoes. Brake shoes are a critical component of drum brakes that push outward against the brake drum to slow or stop the vehicle. Several factors can result in their improper application:
- Worn brake shoes: If the brake shoe material is excessively worn down, it cannot provide the necessary friction against the drum, leading to a reduced braking effect.
- Contaminated brake fluid: Brake fluid can get contaminated with water or other substances, which may affect the hydraulic pressure in the brake system, resulting in inadequate brake shoe application.
- Faulty brake calipers: While brake calipers are not part of a drum brake system (they are part of a disc brake system), a similar component called the wheel cylinder can be faulty and may not apply the correct pressure on the brake shoes.
Thus, all of the above options can potentially lead to improper application of brake shoes, although the answer about calipers should be nuanced as it pertains to disc brakes. Nevertheless, the improper functioning of respective components in different brake systems can cause issues.