What are the brake line fitting sizes?
How brake line fittings are measured
Brake line fittings are divided by the type of flare, either inverted, bubble or DIN, brake line diameter, and thread count.
To measure thread count you’ll need a thread pitch gauge like this:
For SAE applications you’ll be measuring threads per inch. For metric applications, you’ll be measuring threads per millimeter.
Brake line inverted flare versus bubble flare
Most common brake line sizes
Most cars and light-duty SUVS and CUVs use 3/16″ diameter brake line. Larger trucks often use 1/4″ lines.
Posted on by Rick Muscoplat