Over adjusted drum brakes

Drum brakes are adjusted to compensate for normal wear. If they are over adjusted, the brakes can lock up, or be activated with very little pressure on the brake pedal. The brake shoe adjuster resets the distance between the drum and shoe during normal driving. If there is a problem with the adjuster, it can over adjust.

Table of Contents

• 1. Symptoms
  • 1.1 Brakes Lock Up
• 2. Causes
  • 2.1 Defective Brake Shoe Adjuster
  • 2.2 Shoes Over Adjusted on Installation

Symptoms

Brakes Lock Up

The brakes can lock up if over adjusted. The brake shoe will have an initial starting point closer to the drum. If it is too close, the two may make contact and slow the wheel.

Causes

Defective Brake Shoe Adjuster

The brake shoe adjuster pushes the shoe outward as the brake lining wears. The adjuster usually operates when the vehicle is reversing. If the adjuster is defective, it may adjust the shoe when it is not needed, pushing the shoe closer to the drum.

Shoes Over Adjusted on Installation

When new brake shoes are installed, they must be adjusted to the proper point. If the shoe is too close to the drum upon installation, the vehicle has no way of correcting the error. The shoe will remain at a closer starting position and will move even closer to the drum upon adjust from the shoe adjuster.