Subaru Brake Problems: Low Fluid & Pedal Vibration

Had almost the exact same issue with my 2006 Subaru Outback diesel last year. Speaking as someone with moderate experience working on cars, the symptoms you describe match what I encountered. Initially thought it was just low brake fluid, but during the brake inspection the mechanic found worn brake lines and significant wear on the brake pads. The warning light came on shortly after I first noticed the spongy pedal feel. The complete service included: Brake fluid replacement, New brake lines installation, Brake pad replacement, Full system bleeding Total cost came to 480€, which included parts and labor. The workshop completed everything in one day, and the brakes have been working perfectly since. Before giving more specific advice, could you share: current mileage on your vehicle? When was your last brake service? Is the brake warning light illuminated? Are you noticing any fluid spots under the car? These details would help determine if your issue matches what I experienced. Regular brake inspection is crucial, especially on these older Subaru models where brake components tend to wear at predictable intervals.

Thanks for sharing those details. My Subaru has 154889 KM on the clock, and the last service was just brake fluid top-up 6 months ago. No warning light yet and no visible leaks under the car. After reading about your experience with similar hydraulic brake issues, it sounds like I should prepare for more than just a fluid refill. The vibration through the brake pedal is pretty concerning, especially given the age of the brake lines on these G3X models. Going to book a proper brake inspection first thing. Rather catch any worn brake lines or other issues now than risk complete failure later.

Since we dealt with similar brake system problems, I should mention that periodic vibrations through the brake pedal often point to issues beyond just the brake fluid level. In my case with the 2006 Outback, what started as minor feedback eventually revealed problems with the master cylinder and brake lines. Getting it checked at 154k is smart timing. My issues surfaced around 160k, and waiting longer would have likely led to more extensive brake system repairs. The master cylinder was showing early signs of failure, which explained the inconsistent pedal feel you are also experiencing. The fact your brake fluid needed topping up recently without visible leaks suggests the system might be slowly losing pressure somewhere. During my brake inspection, they found microscopic cracks in the brake lines that were not visible to the naked eye. While your symptoms are slightly different, these hydraulic brake problems tend to cascade if left unchecked. Better to have a professional assess the entire system now, particularly checking: Master cylinder operation, Brake line integrity, Caliper function, System pressure retention Feel free to update once you get the inspection results. Curious if your G3X shows similar wear patterns to what I encountered.

Thanks for that detailed feedback. Just got back from the shop after the brake inspection. Turns out my situation is pretty similar to yours, they found hairline cracks in two brake lines and the master cylinder is showing signs of wear. The mechanic showed me where the hydraulic brake system was losing pressure. The full repair quote includes brake fluid replacement, new brake lines, and master cylinder rebuild. Total comes to 520€. A bit more than I hoped but at least I caught it before any major brake system failure. They can fit me in next week for the work. Good thing I didnt just try topping up the brake fluid again and hoping for the best. The vibration through the pedal was definitely a warning sign worth paying attention to. The technician mentioned these issues are fairly common at this mileage. Makes sense given what you experienced with your Outback at around 160k. Appreciate you sharing your experience, helped me understand what I was dealing with.