Audi S1 Brake Warning: Low Fluid & Spongy Pedal Alert

Had this exact same problem with my 2014 Audi S3. As someone with moderate experience working on cars, I can tell you that spongy brakes combined with low fluid usually signals worn brake pads or a potential leak in the system. First step was getting a proper brake inspection done. The warning light and low fluid level pointed to significant wear on my front brake pads and rotors. The workshop also found a small leak in one of the brake lines which explained the constant fluid loss. The full repair included: New brake pads and rotors, Brake line replacement, Fresh brake fluid flush, Full system bleed Total cost came to 480 Euro and took about 4 hours to complete. The brakes feel solid now and the warning light is gone. For your S1, would definitely recommend getting it checked ASAP. Could be something similar, but would need to know: Current mileage? When was your last brake service? Can you hear any squealing when braking? Is the fluid loss gradual or sudden? Best to avoid driving until its properly diagnosed, as brake issues can become dangerous very quickly.

Last service was completed at 23500 KM, just about 3500 KM ago. The master cylinder was inspected and brake fluid levels were normal at that time. The fluid loss seems gradual based on my weekly checks. No squealing noises during braking, but the spongy brake pedal feeling has gotten worse over the last few weeks. I perform regular brake system checks given the sporty nature of the S1. I will schedule a comprehensive brake inspection right away. Theres no point risking safety with compromised brakes. Will report back after the fluid replacement and inspection to share what they find.

Thanks for the additional details about your S1. The symptoms you describe match exactly what I experienced with my brake system. Given the recent service and gradual fluid loss without squealing, I strongly suspect you have a minor leak in the hydraulic brakes system, similar to what I had. The master cylinder check during your last service is good news, as it rules out one major potential issue. However, brake fluid doesnt just disappear on its own. A proper brake inspection should focus on: Checking all brake lines for hairline cracks, Testing the hydraulic system for pressure loss, Inspecting brake caliper seals, Verifying brake pad thickness My leak turned out to be from a deteriorated rubber brake line, a common wear point that often shows up between major services. The gradual fluid loss you mentioned mirrors my experience exactly. When booking the inspection, make sure they plan for a complete brake fluid flush. Even if the leak is minor, contaminated or old brake fluid can cause that spongy pedal feel you mentioned. Would be interested to hear what they find during the inspection. The repair should be straightforward if its just a brake line issue like mine was.

Thanks for explaining how your brake repair went. After hearing about your experience, I've scheduled an urgent brake inspection for tomorrow morning. The similar symptoms definitely have me concerned about potential brake line issues. My weekly fluid checks show its dropping about 2mm below the minimum mark now. Given the critical nature of the brake system, I wont drive it until the inspection is done and any needed repairs are completed. The shop quoted 85 Euro for a full brake inspection including pressure testing. They mentioned being ready to do a complete fluid replacement and brake line inspection if needed, which sounds like the right approach based on your experience. Will create a new post once I get the results back and know exactly what they find. Hoping its just a simple brake line replacement like yours was, rather than anything major with the master cylinder or calipers. Thanks again for sharing the details of your repair, really helped me understand what might be going on with my brake system.