Peugeot 607 brake pedal feedback

I also own a Peugeot 607 with a diesel engine, and I experienced similar symptoms. I found that undervoltage in the vehicle's electrical system can cause erratic behavior in the braking system. Have you checked your battery's condition and the alternator output? Faulty brake pads can cause the same issues, too. Perhaps your brake pads are made of metal?

Thank you for your suggestion. I didn't consider the electrical side. How did you confirm undervoltage as the root cause of your brake issue? I will test the battery, but I'm curious to learn about your troubleshooting steps.

I initially suspected issues like squeaky brakes and brake pads due to the sounds I was hearing. After further investigation, and some consultation, the fluctuations matched undervoltage patterns. Given your symptoms and my experience, it's worth having a workshop perform a thorough diagnostic. A detailed scan could pinpoint the source.

It was indeed related to undervoltage affecting the ABS system. The workshop confirmed it and after fixing that, everything went back to normal. Final repair cost was 240€ Thank you again for your help!