Fittings
Brake Line Tube Nuts
The right connection for every line -- sealed, secure, leak-free.
Tube nuts (also called fittings or flare nuts) thread onto a flared brake line and clamp the flare into the port to make a leak-free seal. Get the size, thread, and flare right and the line seats every time; get one wrong and it will weep no matter how hard you crank it.
Complete the job — you'll also want
Getting the right tube nut
Three things have to match. First the tube size -- most lines are 3/16" (some rear and heavy-truck runs are 1/4"). Second the thread size and pitch. Third the flare style: most American and Asian vehicles use an SAE double (inverted) flare, while many European vehicles use a DIN bubble flare. Match all three to your vehicle and you're set.
Related: Adapters, Unions, Flaring Tools, All Fittings.