Phaeton's Shaky Brake Pedal Signals Disc Wear Issues

Having dealt with comparable brake issues on my 2014 Passat diesel, I can share some relevant experience based on my intermediate-level car knowledge. The symptoms you describe sound very similar. The vibrating brake pedal and inconsistent resistance initially made me think it was just worn brake pads or disc brakes. However, when taken to the workshop, they discovered an undervoltage problem affecting the brake system electronics and hydraulic brake components. The diagnosis revealed that low voltage was causing irregular signals to the brake calipers, leading to uneven brake pressure distribution. After replacement of some electrical components and a full system reset, it cost 240€ to resolve the issue. The squeaking could indicate worn brake pads, but the pedal feedback issues might point to something more complex in the electronic brake management system. To better assist, could you provide: Any warning lights on the dashboard? Does the issue occur more when the engine is cold or warm? Have you noticed any other electrical issues? When was the last time your battery was replaced? The brake pad wear at 40000km since last service is within normal range, but metal brakes should be inspected to rule out mechanical causes.

Thanks for the detailed feedback. Just had a full service at 133511km last month and they checked the battery, its good. No warning lights showing. The vibration happens regardless of engine temperature, and no other electrical issues noted. Upon rechecking, the brake rotors have visible scoring marks when looking through the wheel. Based on the feedback here, I will get the brake system checked. The inconsistent pedal feel combined with visible rotor wear likely points to worn disc brakes needing replacement. Will schedule hydraulic brake system inspection too just to be thorough. The brake fluid was changed during the recent service, so at least that component is fresh. The brake shoes and other mechanical parts definitely need professional evaluation given the symptoms.

Thanks for the update on your brake diagnosis. After reading about the scoring on your brake rotors, this matches exactly what I discovered on my Passat when I had similar symptoms. The scored brake rotors definitely explain the pedal vibration. When brake rotors develop these uneven surfaces, it causes the brake calipers to move irregularly during braking, which transmits that shaky feeling right to your foot through the hydraulic brake system. Since you mentioned your brake fluid was recently changed, we can likely rule out hydraulic brake issues. In my case, replacing the scored brake rotors and brake pads as a set resolved the vibration completely. The total job came to 420€ including new brake calipers, as the mechanic found one was slightly seized. Would recommend having this looked at soon, scored brake rotors can accelerate wear on other brake system components if left too long. The uneven surface causes extra stress on the brake pads and can affect stopping performance. Let us know what the inspection reveals. Curious if your root cause matches what I found with my Passat.

Good feedback regarding the brake rotors and scoring marks. Getting both a mechanical and hydraulic brake system inspection makes sense before moving forward with repairs. The fact that both the squeaky brakes and pedal vibration appeared around the same time suggests they are likely related to the scored brake rotors I can see. Will document the inspection findings here once completed. The repair costs shared are helpful for budgeting purposes. Based on the brake system symptoms described and visible rotor wear, I expect to need at least new brake rotors and pads. Makes sense the uneven rotor surfaces would cause that inconsistent pedal feel through the brake system. Scheduled the car in for next week. The metal brakes definitely need professional evaluation given the symptoms keep getting worse. Will check if any brake calipers are seizing up too since that could contribute to uneven rotor wear. Thanks for helping narrow down the likely causes.