Common Brake Pad Faults and Quick Troubleshooting Guide
Brake pad faults directly affect driving safety. Below are 6 types of high-frequency issues, along with concise identification methods and troubleshooting steps to help quickly diagnose and resolve problems.
I. Brake Noise
1. Sharp "Squeaking" Sound
Symptom: Continuous metallic friction noise when lightly pressing the brake, more noticeable in cold vehicles.
Cause: Brake pads worn down to the metal warning plate, or surface carbonization due to high temperatures.
Troubleshooting:
Check thickness; replace brake pads immediately if < 3mm.
If thickness is sufficient, sand the carbonized layer with sandpaper and apply high-temperature anti-noise grease to the back of the pads.
2. Dull "Thudding" Sound
Symptom: Low-frequency impact noise when braking, accompanied by pedal vibration.
Cause: Detached/broken clips or springs between brake pads and calipers, or rust deformation of the pad backing plate.
Troubleshooting:
Remove the wheel to inspect; replace broken clips.
Sand rust on the backing plate, apply anti-rust grease, and ensure the pads are securely clamped with no looseness.
II. Reduced Braking Performance
1. Longer Brake Pedal Travel
Symptom: Brake pedal needs to be pressed to 2/3 of its stroke to engage, with longer braking distance.
Cause: Excessive brake pad wear, or insufficient/degraded brake fluid, or brake line leakage.
Troubleshooting:
Replace overly worn brake pads.
Refill with brake fluid of the same type; check for line leaks. Replace leaking hoses and bleed the brake system if needed.
2. Braking Pull (Vehicle Drifts)
Symptom: Vehicle drifts to one side when braking; steering wheel must be held firmly to stay straight.
Cause: Uneven wear of brake pads on the same axle, or stuck caliper on one side.
Troubleshooting:
Replace brake pads synchronously on the same axle (do not replace only one side).
Sand rust on the caliper piston, apply grease, and test drive after repair.
III. Abnormal Wear & Special Faults
1. Uneven/Premature Pad Wear
Symptom: One side of the pad is worn to the limit while the other is thick; or service life < 20,000 km.
Cause: Rusty caliper guide pins, poor-quality pads, or caliper failure to retract.
Troubleshooting:
Sand guide pins and apply lubricant.
Replace with certified brake pads; repair caliper piston seals.
2. Cracking/Burnt Smell
Symptom: Brake pad cracks, detached friction material, or burnt smell after braking.
Cause: Poor pad quality, sudden cooling of hot pads with cold water, or stuck calipers causing overheating.
Troubleshooting:
Stop driving immediately and replace pads if cracked/detached.
For burnt smells, stop to cool the pads; repair calipers. Use auxiliary braking (e.g., hill descent control) on mountain roads to reduce pad load.
Core Principles
Prioritize repairing faults; never take "temporarily usable" risks.
Leave complex operations (e.g., brake bleeding, caliper repair) to professional technicians.
Check brake pad thickness monthly; detect and resolve issues early to avoid additional damage.
