How to Adjust Drum Brake Shoes

Occasional adjustment of the drum brakes keeps the brakes in good operating condition.

Drum brakes operate similar to disk brakes. Pressure is placed upon the spinning wheel through brake shoes which creates the stopping power. The difference is in the layout of the brakes. Drum brakes use a metal cylinder called the drum attached to the wheel with the shoes placing pressure on the drum through pistons and springs. Unlike disc brakes, drum brakes become loose with age and use. The lower end of the brake shoes are adjustable which allows the brakes to remain tight. Tightening the drum brakes is something anyone can do.

Things You'll Need

• Drum brake adjustment tool
• Flat-head screwdriver
• Wheel chocks
• Jack
• Jack stands

Instructions

1. Place wheel chocks in front of and behind the tires opposite to the end of the vehicle on which you are working. Place the vehicle in neutral and disengage the emergency brake. Raise the tires you need to adjust so that the wheels are not touching the ground. Raise the vehicle with the jack and place jack stands under each raised wheel at the axle for safety.

2. Leave the tires on the vehicle and climb under the rear axle. On the backside of the drum brakes pointing towards the center of the vehicle, locate a rubber, oval-shaped plug. Remove the plug. This port provides access to the star sprocket adjustment for the drum brakes.

3. Place the drum brake adjustment tool or a flat-head screwdriver inside of the oval or round access hole and note the sprocket that spins the adjustment bolt for the drum brakes. Using a upward motion, put pressure on the sprocket until you feel it click from moving.

4. Test the brake. When properly adjusted, the rear wheel should only spin a single revolution from you manually spinning it lightly. This means that there is slight pressure on the cylinder without excessive pressure. If a light spin sends the wheel spinning freely without stopping for multiple revolutions, repeat step 3.

5. Repeat the process for both sides of the vehicle. Once both tires have equal pressure, replace the rubber plugs which protects the brakes from water and dust entering the cylinder, remove the jack stands and wheel chocks and take the car for a short test drive and test the brakes.

Tips & Warnings

• Rear drum-brakes cannot be adjusted with the emergency parking brake on, as this engages the rear brakes.

• Over-tightening the drum brakes causes excessive wear which could lead to the brakes locking up. To release pressure on the adjustment bolt, you have to remove the tire and drum and manually loosen the pressure. If your rear brakes are still not grabbing properly after adjusting the drum brakes to proper tension, you may have a piston or brake line issue. Consult a professional for further diagnosis.

References

• Auto Media: Drum Brake Adjustment