* Reduced braking performance: This is the most obvious sign. If you feel the car takes longer to stop than usual, especially when braking hard, it could indicate worn-out brake shoes or drums.
* Grinding or squealing noises: These sounds often indicate metal-on-metal contact, meaning the brake shoes are worn down to their wear indicators or the drums are scored or damaged.
* Spongy or soft brake pedal: This suggests a loss of hydraulic pressure in the brake system, which *could* be due to severely worn-out drums, though other issues (like a leak) are more likely causes. It's crucial to get this checked immediately regardless.
* Visible wear on brake shoes: If you inspect your brake shoes (after removing the drums – *don't* try to judge wear just by looking into the drum opening), you'll see wear indicators – often small metal tabs or grooves – that will tell you when the brake shoes need replacing. If these are worn down or close to it, it’s time for new shoes and potentially drums.
* Damaged or scored drums: If you remove the drums, you might see deep grooves, scoring, rust, or other damage on the drum surfaces. Deep scoring can compromise braking effectiveness and prevent proper shoe contact. Rust can lead to sticking or uneven braking.
* Drums that are excessively thin: Drums have a minimum thickness specification. If they're below this, they're unsafe and need replacement. A mechanic will have a gauge to measure this.
* Leaking wheel cylinders: Wheel cylinders are part of the hydraulic system within the drum. Leaks will lead to brake fluid loss and significantly weakened braking. This often requires drum removal to repair/replace.
Important Note: While some minor surface rust might be acceptable, extensive rust, deep scoring, or wear below the minimum thickness requires drum replacement. It's best to have a qualified mechanic inspect your drums and brake system to diagnose the problem and determine if replacement is necessary. Don't attempt major brake repairs yourself unless you have significant mechanical experience. Compromised brakes are incredibly dangerous.
