Suspension & brakes
Rear brake line corrosion (salt-state recalls)
Salt gets past the fuel-tank protector and corrodes the steel brake lines above the tank and at the rear fittings. Subaru recalled the lines twice for cars in snow-belt states; owners still report sudden fluid loss on cars that were repaired or never came in.
Frequency basis: Two NHTSA recalls (13V-110 and 14V-311, Subaru campaigns WQG-43 and WQK-47) cover 2005–2009 Outbacks registered in salt states, and 15 of 273 NHTSA complaints describe the brake pedal going to the floor from a leaking line, some after the recall work. NHTSA's brakes category holds 42 complaints. Wisconsin is a listed recall state.
Symptoms
- Brake warning light, low pedal, pedal to the floor with the car still moving
- Brake fluid wet spots near the rear of the fuel tank or at the rear flex-hose fittings
- Reservoir level dropping with no leak at the calipers
Causes found
- Salt water trapped behind the fuel tank protector corroding the hard lines (the recall defect)
- Rust at the rear hard-line to flex-hose fittings and along the lines in the rear wheel wells
Check in this order
- Run the VIN through the NHTSA recall lookup and confirm WQG-43 / WQK-47 were completed
- Inspect the lines above the tank, at the rear fittings and in the wheel wells every year in a salt state
- Treat any fluid loss as a stop-driving fault
What fixed it
- Dealer recall repair: inspect, apply anti-corrosion wax, replace corroded lines at no charge if the recall is open
- Replace corroded lines with properly flared steel or copper-nickel tubing and bleed the system; no compression fittings
- Replace rear flex hoses while the lines are apart
References on this site
Factory manual chapters
Maintenance guides
Sources
Forum threads are owner reports, not factory findings. Counts are from the threads and complaint records read for this page; read the sources before buying parts.
- 1.NHTSA recall 14V311000: brake lines, 2005-2009 Outback and Legacy
nhtsa.gov · NHTSA · salt-state recall, received 2014-10-06
- 2.NHTSA recall 13V110000: brake lines, 2005-2009 Outback and Legacy
nhtsa.gov · NHTSA · earlier salt-state recall, received 2013-03-27
- 3.NHTSA complaints, 2005 Subaru Outback
nhtsa.gov · NHTSA · 15 narratives describe brake-line fluid loss, some post-recall
- 4.2005 Subaru Outback problems
carcomplaints.com · Complaint aggregator · brakes: 42 NHTSA complaints