Rear drum brakes that are failing typically show a soft or sinking brake pedal, unusual noises such as squealing or grinding, pulling to one side when braking, reduced braking efficiency, or a parking brake that won’t hold. If you notice any of these signs, arrange a brake inspection promptly.
How rear drum brakes work and what wears out
Most vehicles that use drum brakes on the rear axle employ a pair of shoes inside each drum. When you press the brake pedal, hydraulic pressure pushes wheel cylinders that force the shoes outward against the drum’s interior. Friction slows the wheel, and heat is managed by the drum and surrounding components. The rear brakes also commonly double as the parking brake, using a separate mechanism to apply the shoes when you pull the parking brake lever or push the pedal. Over time, the friction material on the shoes wears down, the drum surface can glaze or become scored, and hydraulic components like wheel cylinders can develop leaks. Inspecting the shoes, drums, wheel cylinders, springs, and parking-brake linkage is essential for reliable rear braking performance.
Common signs your rear drum brakes may be bad
Below are the most frequent indicators that the rear drum brakes may be in need of service. Note that some issues can mimic other brake problems, so professional diagnosis is advised.
- Soft, spongy, or sinking brake pedal that drops toward the floor
- Unusual noises such as squealing, grinding, or scraping when braking
- Vehicle pulls to one side during braking or pedals vibrate/pulse
- Longer stopping distances or reduced braking power
- Poor or inconsistent parking-brake engagement; brake won’t hold
- Visible leaks or dampness around the wheel cylinder or backing plate
- Worn, glazed, cracked, or scored brake shoes or drum interior
- Contamination from oil or brake fluid on the drum or shoes
- Burning smell after heavy or repeated braking
Notice any of these signs? Schedule a brake inspection promptly. Driving with faulty brakes can risk your safety and that of others on the road.
How to diagnose and what to do
To confirm a drum-brake issue and determine repairs, follow these practical steps. If you are not comfortable with brake work, have a professional inspect.
Safety and preparation
Brake work can be dangerous. Before starting, park on a level surface, chock the wheels, wear eye protection, and use jack stands rated for your vehicle. If you’re unsure at any point, stop and seek professional help.
- Visually inspect the drum and shoes: Remove the wheel and inspect the interior of the drum for deep grooves, scoring, cracks, or glazing. Check the brake shoes for uneven wear or contamination by oil or grease.
- Check shoe thickness and drum condition: If the friction material on the shoes is worn down to the minimum spec in your manual (often a few millimeters), replace the shoes. Inspect the drum inner surface for out-of-roundness or scoring; drums that are out of round or badly scored may need resurfacing or replacement.
- Inspect for hydraulic leaks: Look for seepage around the wheel cylinder and on the backing plate. A leaking wheel cylinder will require replacement and possibly a brake-fluid bleed.
- Check the parking brake mechanism: Inspect the cable, adjuster, and RELEASE arm. A sticking or stretched cable can cause poor parking-brake performance. Adjust or replace components as needed per factory service procedures.
- Perform a controlled road test: With light pressure, test braking at low speed in a safe area. Listen for noises, feel for pulling, and note pedal feel. If the pedal sinks or the brakes feel soft, stop and recheck for leaks or air in the hydraulic system.
- Decide on repair or replacement: If shoes are worn or contaminated, replace them (and consider resurfacing or replacing the drum if necessary). If wheel cylinders leak or the drum is severely scored or out of spec, replacing the affected parts is usually required. In many cases, replacing the shoes in pairs and servicing both drums is recommended for balanced braking.
- Test again after repair: Reinstall wheels, bleed the system if fluid was replaced, and perform a final test at low speed to ensure the brakes engage evenly and hold when the parking brake is applied.
Concluding: Brake work should be done with care and, when in doubt, by a professional. Proper adjustment and correct parts are essential for safe braking performance.
Summary
Rear drum brakes can degrade gradually. Key signals include a soft pedal, unusual noises, steering pull during braking, reduced stopping power, or a parking brake that won’t hold. Regular visual checks of shoe thickness, drum condition, wheel-cylinder seals, and the parking-brake linkage help catch problems early. When symptoms appear, have the system inspected and serviced by a qualified technician to ensure reliable and safe braking.