What Causes the Reversing Brake Squealing in BMW 5 Series?
2 Answers
Squealing reasons primarily include brake noise when the car is new, resembling friction sounds or sharper squealing, which is normal during the break-in period. If the noise is particularly sharp, it might be due to small stones trapped between the brake disc and pad or a water film. Check if the car shock absorber screws are loose or leaking, whether the chassis screws are loose, and if chassis components have aged. Brake disc wear: Severe brake disc wear causing noise If the brake disc is severely worn, the outer edge where the brake disc and pad do not make contact becomes a raised ridge relative to the friction surface. When the corner of the brake pad rubs against this ridge, it may produce noise. Warning indicator: The warning indicator emits a sharp squeal to prompt replacement Typically, vehicles have a warning system in the braking system to alert owners to replace brake pads. When the brake pad wear exceeds the set warning value, the warning indicator emits a harsh squeal to remind the owner to promptly visit a repair shop for inspection or replacement of new brake pads.
I've been driving a BMW 5 Series for a while now, and it's quite common to hear strange noises when braking in reverse, especially in underground parking lots or after rain in humid conditions. The sounds are mostly squeaks or chirps, which could be due to dust or small stones stuck on the friction surface of the brake pads, or rust on the brake disc surface that hasn't been worn off properly. The different load during reverse braking makes it easier for these sounds to occur. Additionally, BMW models' rear brake designs tend to accumulate moisture, and the lower starting force in reverse can cause uneven contact between the pads and discs. If you frequently hear these noises, it's advisable to visit a BMW dealership as soon as possible to check the thickness and wear condition of the brake pads. If the wear exceeds the limit, new pads will be needed. Don't ignore this issue, as prolonged neglect can lead to uneven disc wear or reduced braking performance, resulting in more expensive repairs later. While reverse braking noises don't always indicate major faults, regular car washing and brake system maintenance can effectively prevent them, ensuring safe and worry-free driving.
