Spongy Brakes & Fluid Loss Signal Master Cylinder Trouble

Had similar brake pedal problems with my 2006 A3 TDI at 142000km. The spongy pedal feel and low brake fluid level are classic symptoms of air in the hydraulic brakes system or a potential leak. The master cylinder is a possibility, but its often brake lines or caliper seals that fail first. In my case, the brake system had developed a slow leak at the rear caliper, allowing air to enter. The spongy pedal was the first warning sign. This is a serious safety concern that needs immediate attention. When my brake pedal started feeling soft, the entire brake system needed inspection. The mechanic found corroded brake lines which made the system lose pressure. They had to replace the lines and do a complete fluid replacement to restore proper brake pedal feel. Key warning signs to watch for: Brake fluid spots under the car, Brake warning light, Decreased braking performance, Pedal slowly sinking to the floor Would strongly recommend getting this checked soon. These symptoms typically worsen quickly and brake failure risks are not worth taking.

Thanks for the detailed response about the brake system issues. Turns out you were right about the leak, my mechanic found a corroded brake line that was slowly losing fluid and letting air into the system. They did a full brake fluid flush and replaced the damaged line. Curious what the repair cost was in your case? Mine came to 380 Euro for parts and labor. Also wondering if youve had any other brake-related problems since getting it fixed? My brake pedal feels firm again but the warning light still comes on occasionally when starting the car.

Had my repairs done last week. The total came to 480 Euro which included replacing worn brakes, fixing the brake fluid leak, and a complete system flush. The price was higher than yours since they also found the brake pads were quite worn. The brake pedal issue has been completely resolved since the repair. The spongy feel is gone and the brake fluid level is now staying consistent. These are good signs that the hydraulic brakes are working properly. About your warning light, this could indicate the brake fluid level sensor needs adjustment or replacement. When my master cylinder work was done, they had to recalibrate the sensor to stop false warnings. Might be worth mentioning at your next service visit. My braking system has been trouble-free since the repair. Just make sure to check brake fluid levels regularly and watch for any changes in pedal feel. Regular maintenance helps catch issues before they become major problems.

I wanted to give a quick update on my brake repair situation. After getting the work done this morning, Im feeling much better about the whole thing. The mechanic showed me the corroded brake line that was causing all the trouble. It was pretty bad, all rusty and leaking brake fluid slowly. They ended up doing more than just fixing the line. Had to flush the entire brake system to get rid of any air and old fluid. The brake pedal feels solid now, much better than before. Total cost was 380 Euro which seemed fair for the amount of work they did. Only thing still bugging me is this warning light that keeps showing up when I start the car. The master cylinder and brake fluid levels look good, so Im going to have them check the sensor next time. At least the brakes are working properly now and I feel safer driving. Thanks for helping me diagnose the problem. Would have probably waited longer to get it fixed if I hadnt known how serious these symptoms can be with the brake system.