When to replace brake pads?

I. Judgment by wear warning signals

Abnormal noise prompt

When the brake pads wear to the limit, the internal metal warning piece will rub against the brake disc, producing a sharp "sizzling" sound or metallic friction noise. Immediate replacement is required at this time.

Dashboard warning light

Some vehicle models are equipped with brake pad wear sensors. When the thickness is lower than the threshold, the dashboard will display a warning light similar to "ⓑ" or "brake pads," requiring prompt inspection.

II. Inspection by brake pad thickness

Visual observation of thickness

The thickness of a normal new brake pad is approximately 10-15mm. When it wears down to a remaining 3-5mm (about the thickness of a coin-for example, a one-yuan coin is about 2mm thick, and the remaining thickness is less than that of two coins stacked), replacement should be done as soon as possible.
You can observe the thickness of the brake pads through the gap in the wheel hub, or go to a repair shop for measurement with professional tools.

Abnormal wear of the brake disc

If the brake pads are excessively worn, the brake disc will directly rub against the metal backplate, causing obvious scratches, grooves, or overheating on the surface. In this case, both the brake pads and the brake disc need to be inspected and replaced simultaneously.

III. Judgment by driving feel

Prolonged braking distance

After stepping on the brake pedal, the vehicle's braking effect is significantly weakened, and more force or deeper depression is needed to stop the vehicle, indicating a decline in the friction performance of the brake pads, which requires timely replacement.

Abnormal brake pedal

When stepping on the brake, the pedal shows an obvious "spongy feeling" or abnormal vibration, which may be caused by uneven wear or poor fitting of the brake pads. Inspection and replacement are required.

IV. Combination of usage scenarios and mileage

Routine replacement mileage

Urban commuting vehicles: Usually replaced every 40,000-60,000 kilometers, specifically affected by driving habits (e.g., frequent emergency braking accelerates wear).

High-speed or long-distance vehicles: Wear is relatively slower, and inspection and replacement can be extended to 60,000-80,000 kilometers.

Early replacement for special working conditions

Vehicles with frequent heavy loads, frequent downhill driving (such as trucks or vehicles used in mountainous areas), or aggressive driving styles (emergency braking, high-speed braking) will cause faster wear of brake pads. It is recommended to inspect them every 20,000-30,000 kilometers.

V. Other precautions

Synchronized inspection of left and right wheels

Brake pad wear may be unsynchronized on the left and right due to vehicle load, braking habits, etc. The brake pads of all four wheels should be inspected simultaneously to avoid braking imbalance.

Inspection during regular maintenance

During each vehicle maintenance (such as oil change), you can request the technician to inspect the thickness of the brake pads simultaneously to prevent potential problems.

Summary

When abnormal noise, warning lights, thickness less than 3mm, or weakened braking effect occur, the brake pads must be replaced immediately to avoid brake failure caused by excessive wear, which affects driving safety.

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