Spongy VW Phaeton Brakes After Recent Service Work

Recently dealt with nearly identical symptoms on my 2011 VW Passat. The spongy brake pedal combined with low brake fluid typically indicates a leak in the hydraulic brake system. In my case, the master cylinder was leaking where it connected to the brake lines. When the brake pedal feels inconsistent and the warning light activates, it often points to air entering the brake lines. This is a serious safety issue that needs immediate attention. The master cylinder might not be maintaining proper pressure, or the brake lines could have developed small leaks at connection points. My repair required replacing the master cylinder and bleeding the entire brake system to remove air bubbles. The mechanic also inspected all brake lines for potential leaks and replaced several corroded connection fittings. Given your Phaeton just had brake work done, there could be air trapped in the system from improper bleeding, or a fitting might not have been properly tightened. The brake system should be inspected immediately, loss of brake pressure can lead to complete brake failure. Worth noting that both the Phaeton and Passat share similar brake system components, and these issues are relatively common after the 80000km mark when seals begin to wear.

Thanks for sharing your Passat brake repair experience. That master cylinder issue sounds exactly like what I am dealing with on my Phaeton. Did you remember roughly how much you paid for the complete brake fluid replacement and master cylinder work? Just trying to get an estimate before heading back to my mechanic. Also curious if you have had any other brake-related problems since the repair? The warning light situation has me extra cautious about potential underlying issues that might need addressing while they have it in the shop.

Had the Passat checked right away and thankfully it ended up being less severe than anticipated. The warning light and spongy brake pedal were mainly due to low brake fluid caused by worn brake pads and rotors that needed replacement. The master cylinder was actually fine after inspection. The complete brake fluid replacement and system bleeding fixed the immediate issue. Total repair cost came to 480€ including new pads, rotors, and fresh brake fluid. The brake lines were all in good condition, so no additional work was needed there. Have not experienced any brake problems in the 8 months since the repair. The brake pedal feels firm and consistent now, and the warning light has stayed off. Would definitely recommend having your Phaeton thoroughly checked, especially the brake fluid levels and master cylinder, given the similarity of symptoms. When brake issues pop up its always worth getting a complete system inspection. Better to catch any potential problems early before they become more serious or expensive to fix.

I took my Phaeton back to the shop yesterday after reading about your experience. Turns out my issue was actually more serious than yours, they found the master cylinder was indeed failing, causing the brake fluid to leak slowly. The brake warning light was definitely trying to tell me something important. The complete repair came to 850€, which included replacing the master cylinder, flushing the entire brake system, and bleeding the brake lines properly. The mechanic showed me where the old master cylinder was leaking and explained how it was affecting the brake pedal response. Since picking up the car this morning, the brake pedal feels much firmer and more responsive. The warning light is now off and the brakes work exactly as they should. The mechanic also did a thorough check of all brake components while they had it apart, confirming everything else was in good condition. Really glad I had this checked out quickly rather than waiting for it to get worse. The car brakes now feel better than they have in months.