
Reasons for brake noise in the 2018 Bora: 1. Brake disc break-in period: Whether it's a new car or newly installed brake discs, during the initial use, the brake discs and pads have not yet fully matched, which can result in sharp noises during hard or sudden braking. This is a normal phenomenon and not a malfunction. 2. Continuous hard braking: When performing consecutive hard brakes, thermal fade may occur. Two specific manifestations of thermal fade are significantly reduced braking force and unusual sharp noises, commonly referred to as brake noise. 3. Excessive brake pad wear: When the brake pads wear down to the critical point, the thickness warning metal piece on the pads will directly rub against the brake disc, producing an abnormal and harsh sound. This indicates that the brake pads are excessively worn and must be replaced. 4. Excessive brake disc wear: When the thickness of the brake disc falls below the critical point, the metal edge surrounding the disc will come into direct contact with the brake pads, not only causing loud noises but also potentially leading to brake failure and severe body vibrations.

My 2018 Bora makes squeaking noises when braking in winter. Inspection revealed that the OEM brake pads contain high metal content, causing hard friction against the brake discs in low temperatures, similar to nails scratching a blackboard. Moisture can also lead to rust spots causing friction. The repair shop said this is common in cars, suggesting either smoothing the edges of the brake discs or switching to ceramic brake pads as solutions. They also found that the spring clip in the brake pad slot is loose, causing a rattling noise on bumpy roads, which requires wheel removal for tightening. While long-term neglect won’t affect braking performance, the noise is annoying and can lead to excessive disc wear. It’s better to address these minor issues promptly rather than delay.

The brake noise issue in the Bora is mostly attributed to the metal caliper structure. From my experience: First, ensure the wheel bolts are tightened to specification (over-tightening can warp the brake disc). Next, inspect whether the dust shield is deformed and rubbing against the disc. Some 4S dealerships may upgrade the noise suppression shims or apply copper-based grease to eliminate friction sounds between the pads and caliper. The key is observing the noise pattern – if it occurs when reversing a cold car, it's usually a material issue; if it happens at the moment of full brake application, check for uneven wear on the brake disc. For MQB platform vehicles, the rear wheels tend to accumulate mud and sand, so cleaning the guide rail grooves might yield positive results.

Excessive impurities in brake pads may cause abnormal noises. I've disassembled the brake pads of an 18-model Bora, and found that some batches had uneven metal particles in the friction material, causing resonance at specific frequencies during high-speed braking. In extreme cases, a mirror-like reflective layer may form on the brake disc surface, requiring sandpaper treatment to roughen it. It's recommended to record the vehicle speed and braking force when noises occur: check the caliper for noises during low-speed light braking, examine the fit between disc and pad for heavy braking noises, and consider directly switching to ceramic pads if there's persistent high-pitched squealing in rainy conditions, as the drainage groove design of OEM pads isn't outstanding.

Metal knocking sounds should prioritize checking the dust cover. Once while repairing my own car, I found the metal cover deformed due to heat, only half a millimeter away from the brake disc, causing a tapping collision when bumpy, sounding like a loose part. If it's a high-frequency squeal, it's most likely the brake pad warning tab touching the disc (automatic reminder when thickness is below 3mm). Remember to check the brake fluid level, as excessively low levels may affect caliper retraction causing dragging noises. Safety is no small matter - these checks can be done yourself in just twenty minutes.

The 2018 Bora's brake noise issue is frequently complained about in car owner groups. There are three core causes: the brake pads' metal formula being too hard; insufficient lubrication of the caliper guide pins causing slow retraction; and the VW factory brake discs' heat treatment process leading to raised edges. Solutions vary by severity—minor noise can be fixed with a brake disc chamfering tool for edge trimming, while persistent noise requires replacing the pads with noise-reducing coated versions plus applying high-temperature anti-squeal paste. Some owners report dealerships upgrading the brake spring models, which is one of the manufacturer's acknowledged TSB solutions.


