Automobile & Light Truck Certification Test A5 BrakesHydraulic System Diagnosis and RepairMedium
A technician is inspecting a vehicle's hydraulic brake lines and discovers a section of steel brake line that is severely corroded, but not yet leaking. The technician also notes that the corrosion is primarily surface rust, but it has started to pit the line. What is the MOST appropriate action?
- AWrap the corroded area with electrical tape or a hose clamp to prevent further damage.
- BReplace the entire corroded section of the brake line with a new steel line.
- CClean the corroded area with a wire brush and apply rust-inhibiting paint.
- DMonitor the corrosion and re-inspect at the next service interval.
Show answer & explanationAnswer & explanation
Correct answer: B. Replace the entire corroded section of the brake line with a new steel line.
Any significant corrosion or pitting on a steel brake line compromises its structural integrity and can lead to sudden failure under hydraulic pressure. Even if not currently leaking, the line is weakened. The only safe and correct repair is to replace the affected section of the line, or the entire line if the corrosion is widespread.
Why the other options are wrong
- A. Wrapping with tape or a clamp is a temporary, unsafe 'fix' that will not prevent eventual failure.
- C. Cleaning and painting only addresses surface appearance; it does not restore the structural integrity of a pitted line.
- D. Monitoring a severely corroded and pitted line is dangerous and irresponsible; it should be replaced immediately.
Brake Line Corrosion
Degradation of steel brake lines due to rust and environmental exposure, leading to reduced strength and potential leaks.
- Pitting corrosion is more dangerous than surface rust.
- Compromises hydraulic pressure integrity.
- Requires replacement, not repair, for safety.
Memory trick: Brake lines: if it's pitted, it's quitting.