System Characteristics

Brake Noise 

Brake noise can occur and to a degree, some brake noise is normal. Variations in driving conditions such as the weather, environment, driving patterns, differences in vehicle loading and type or style of driving, can affect brake wear. Any one of these variations can cause brake noise to become apparent. Inspect and verify that all metal-to-metal contact areas of the brake shoes to the self adjusters, anchor pins and backing plate, are clean and free of corrosion and scale.

Brake noise is a "slip-stick" vibration of drum brake components and, if it occurs intermittently, can be considered normal. Most brake noise may be eliminated or temporarily reduced by performing 3 or 4 aggressive brake applications. If the brake noise persists or consistently recurs, application of a damping compound to the brake shoe mounting plate where it contacts the backing plate can lessen the vibration as the components move relative to each other.

The following brake noises are characteristic of all brake systems. These noises cannot be avoided and may not indicate improper operation of the brake system.

Squeak/Squeal Noise 

A squeak or squeal noise can occur on vehicles with front semi-mettalic brake pads during light to medium brake pedal application at low to moderate vehicle speeds. Occasionally this noise may appear from the front or rear brakes after a period of non-use such as overnight or cold brakes and/or in high humidity conditions.

Grinding Noise 

Common occurrence for rear brakes and some front disc brakes during initial brake applications after the vehicle has been parked overnight. Caused by light corrosion forming on the metal brake component friction surfaces during vehicle non-use. Typically disappears after the first few brake applications.

Groan Noise 

A groan type noise may be heard during a quick stop or when slowly moving forward from a complete stop. On vehicles equipped with antilock brake systems (ABS), a groan or moan noise may occur during heavy brake application or on road surfaces with compromised traction such as loose gravel or on wet or icy roads. This is a normal function of ABS activation.

Brake Shoe Clap 

A slight tapping noise from the drum brakes during brake application. This noise may be due to the brake shoes following the light spiral pattern evident on the brake drum after machining on a brake lathe. This noise will generally lessen or disappear with time and repeated use of the brakes during normal vehicle operation.