Michigan State Brakes Certification Practice Exam

If the front brakes of a car equipped with disc brakes in the front and drum brakes in the rear grab quickly with light pressure, what could be the issue?

1. Low brake fluid level

2. Glazed rear shoes

3. Defective metering valve

4. Too much brake fluid pressure

The correct answer is: Defective metering valve

A car exhibiting rapid grabbing of the front brakes with light pressure may indicate an issue with the metering valve. The metering valve is responsible for controlling the brake pressure applied to the front disc brakes, ensuring that the front and rear brakes engage proportionally to maintain effective braking performance. If the metering valve is defective, it may deliver too much pressure to the front brakes relative to the rear, causing them to engage abruptly even with slight input from the driver. This can lead to a loss of control or uneven braking performance, which is particularly noticeable with the sensitive nature of disc brakes. In contrast, low brake fluid level can lead to spongy brakes or reduced braking power, rather than grabbing. Glazed rear shoes typically cause a loss of braking effectiveness or noise due to reduced friction, rather than an abrupt engagement of the front brakes. Excessive brake fluid pressure could potentially contribute to grabbing, but in this context, the focus on the specific function of the metering valve provides a more precise explanation for the observed behavior in the front brakes.