In a vehicle with disc front brakes and drum rear brakes, what could cause the front brakes to grab quickly with light pedal pressure?

The correct answer highlights the role of the metering valve in a vehicle's braking system. In a braking setup that features disc brakes in the front and drum brakes in the rear, the metering valve acts as a crucial component that manages the hydraulic pressure applied to both types of brakes during operation.

When brake pedal pressure is applied, the metering valve ensures that the front disc brakes do not engage too quickly compared to the rear drum brakes, preventing premature locking of the front wheels. If the metering valve is defective, it can fail to regulate brake pressure appropriately. This could lead to a situation where light pedal pressure causes the front brakes to engage abruptly or "grab" since the control over pressure modulation is compromised.

In this context, an improperly functioning metering valve can create safety issues by distributing brake force unevenly, increasing the risk of losing control of the vehicle during braking. This scenario explains why the specific malfunction of the metering valve is linked to the problem described in the question.

Other components mentioned in the choices interact differently with the braking system. An overfilled brake fluid reservoir could lead to leaks or overflow but is less likely to directly affect the immediate feel of the brakes under light pressure. Worn brake shoes typically affect drum brakes