VW Golf TDI Brake Issues: Fluid Loss & Pedal Problems

As someone with moderate experience maintaining diesel vehicles, I faced nearly identical brake issues with my 2016 Golf GTD last year. The symptoms you describe closely match what I experienced, that characteristic spongy pedal feel is often a red flag for brake system problems. The brake inspection revealed worn brake pads and slightly warped rotors, which explained the pulsing sensation. While low brake fluid was indeed part of the issue, it turned out to be a symptom rather than the root cause. As brake pads wear down, the fluid level naturally drops to compensate. I ended up needing a complete brake service that cost 480€, including: New brake pads, Brake fluid replacement, Rotor resurfacing, Full system inspection The warning signs you describe definitely warrant a professional brake inspection rather than just topping up the fluid. Brake issues should never be ignored as they directly impact safety. To provide more specific guidance, could you share: Current mileage on your vehicle, When was your last brake service, Whether you notice any squealing sounds during braking, If the brake warning light has illuminated on your dashboard This information would help determine if your situation mirrors what I experienced with my GTD.

Thanks for the feedback. My last service was 7 months ago at 130000km. No squealing sounds, and the brake warning light only appears when starting the car but goes off immediately. The master cylinder might be the issue since the brake fluid keeps dropping despite no visible leaks. A mechanic told me last time the hydraulic brakes were functioning correctly, but the pedal feel has definitely changed since then. The brake fluid is due for replacement according to the service schedule, so I will get that done along with a thorough inspection of the whole braking system to be safe. Current mileage: 138157km

Thanks for those details. Your situation sounds very similar to what I experienced, but my Golf GTD had slightly different symptoms that ultimately revealed a more complex issue. After my initial brake fluid and pad replacement, I noticed the fluid level kept dropping gradually without visible leaks, just like yours. The master cylinder turned out to be slowly failing, allowing internal seepage that wasnt detectable from outside the brake system. The repair ended up including: Master cylinder replacement (680€), Complete brake fluid flush, Brake line inspection The total repair restored proper pedal feel and solved the fluid loss completely. Since your vehicle has comparable mileage to when mine failed (I was at 142000km), and the symptoms match, I strongly suspect your master cylinder might be showing the same wear pattern common to these models. The fact your brake warning light behaves normally is good news, as it suggests the hydraulic brakes are still functioning safely. However, waiting too long could lead to more extensive brake system damage. Would recommend scheduling that brake inspection soon, specifically asking them to pressure test the master cylinder along with the routine brake fluid replacement. This might save you from discovering a bigger problem later.

Thanks for the detailed feedback. The symptoms you described with the master cylinder failing seem to match what I'm experiencing with my brake system. Given the similar mileage when your issues occurred, I will definitely have them check the master cylinder during the inspection. The brake fluid keeps dropping without visible leaks, just as you mentioned, which does point to potential internal seepage in the hydraulic brakes. I have already scheduled a full brake inspection for next week. Asked them specifically to: Pressure test the master cylinder, Replace the brake fluid, Check all brake lines for leakage, Inspect brake pads and rotors The estimated cost is around 750€ if the master cylinder needs replacement, plus labor. While not cheap, ensuring the brake system works properly is worth the investment. Will update once I know the actual cause of the spongy brake pedal feel. Thanks again for sharing your experience. It helped me understand what potential issues to look out for during the inspection.