Automobile & Light Truck Certification Test A5 BrakesHydraulic System Diagnosis and RepairMedium

A technician is replacing a corroded steel brake line. After installing the new line, they must form a new flare. Which type of flare is typically used for automotive brake lines in domestic and Asian vehicles?

  1. AAN flare
  2. BDouble flare (inverted flare)
  3. CBubble flare (ISO flare)
  4. DSingle flare
Show answer & explanation

Correct answer: B. Double flare (inverted flare)

The double flare, also known as an inverted flare, is the standard for most automotive brake lines in domestic and Asian vehicles. It provides a strong, leak-proof seal under high pressure.

Why the other options are wrong

  • A. AN flares are typically used in aviation and high-performance racing applications, not standard automotive.
  • C. Bubble flares (ISO flares) are common in European vehicles, but less so in domestic and Asian.
  • D. Single flares are generally not used for high-pressure brake lines due to their weakness.

Double Flare (Inverted Flare)

A two-stage flare used on hydraulic brake lines to create a strong, leak-proof seal, common in domestic and Asian automotive applications.

  • Creates a double wall for strength
  • Used with inverted flare fittings
  • Standard for high-pressure brake lines

Memory trick: For brake lines, double up the flare, for safety and pressure beyond compare!

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