VW Golf Hybrid Brake Issues: Spongy Pedal & Grinding

Having some experience with hybrid vehicles, I encountered a very similar issue with my 2016 VW Passat GTE, especially the spongy brake pedal and grinding noise you described. The hydraulic brake system in hybrid vehicles is more complex due to the regenerative braking integration. In my case, the problem turned out to be an undervoltage issue affecting the brake system controller, which caused inconsistent brake response and occasional grinding sounds when switching between regenerative and conventional braking. The workshop diagnosed it using specialized diagnostic equipment for hybrid systems. The repair involved recalibrating the brake system controller and checking all brake calipers for proper operation. Total cost was 240€ including diagnostic work. Before jumping to conclusions about worn brake pads though, could you share: Current mileage on your Golf? When was the last brake service performed? Does the grinding noise happen only during light braking or also during harder stops? Have you noticed any changes in the regenerative braking behavior? This information would help determine if your symptoms match what I experienced or point to a different brake system issue.

Last service was at 108000km. After getting the regular brake inspection, I discovered worn brake rotors and significant deterioration of the brake shoes on the rear. The metal brakes were showing clear signs of uneven wear. The grinding happens mainly during light braking but seems more noticeable after being parked overnight. The regenerative braking feels normal, but the transition to hydraulic brakes isnt as smooth as before. The brake calipers appear to be moving freely when inspected, which suggests they might not be the primary issue. Based on the symptoms described, would replacing just the rotors and brake shoes be sufficient, or should I consider a more comprehensive brake system overhaul?

This definitely aligns with what I experienced on my Passat GTE. The symptoms you describe match almost exactly what I dealt with, especially the overnight parking effect and the transition issues between regen and hydraulic braking. With worn rotors and deteriorated brake shoes already confirmed, I would strongly recommend replacing both rotors and brake pads as a complete set. When I faced similar issues, replacing just the pads didnt fully resolve the squeaky brakes and uneven braking feel. In my case, the disc brakes showed similar uneven wear patterns. While the calipers were also moving freely, the mechanic discovered minor scoring on the brake rotors that wasnt immediately visible. This was contributing to the grinding noise during light brake application. The full brake service I had done included: New front and rear rotors, Complete set of brake pads, Brake fluid flush and replacement, Recalibration of the hybrid brake control module Total cost came to around 850€ including parts and labor. While this might seem extensive, it completely resolved both the grinding and the spongy pedal feel. The braking system has performed flawlessly since then. Most importantly, proper calibration of the regenerative to hydraulic brake transition is crucial for hybrid vehicles. A complete overhaul ensures all components work together correctly.

Thanks for all the feedback. Based on the symptoms and your similar experiences, I think I'll go ahead with the complete brake system overhaul rather than just replacing individual components. The uneven wear on the metal brakes and deteriorated brake shoes, combined with the spongy pedal and grinding, seems to indicate multiple parts need attention. Looks like the comprehensive service package with new rotors, brake pads, fluid flush and recalibration makes the most sense, even though it costs more upfront. Rather get everything sorted properly than have ongoing issues with the brake calipers or hydraulic brakes system. The transition between regenerative and standard braking needs to work smoothly for safety. Will schedule the full brake service for next week and make sure they do the proper hybrid system calibration too. The 850€ cost estimate helps set realistic expectations. Having squeaky brakes and unreliable braking performance isnt worth the risk of trying to save money with partial repairs. Thanks again for confirming my suspicions about needing more than just basic pad replacement. Will update once the work is done to confirm if it resolves all the symptoms.