Brake lines are important parts of your car, because without them your brakes won't function. Rust will not only weaken your brake lines, but can eventually cause them to fail. In the interest of safety, make sure that your lines are as safe from rust as you can make them.
Make sure there isn't any rust on your brake lines. If there is rust you should replace them so you have new or nearly new brake lines to work with. Also, make sure you know the material your brake lines are made of. Stainless steel may not need any special help to avoid rust, whereas regular steel will benefit from additional protection.
Coat the brake line with rust resistant paint primer. Apply a full coat of the primer and let it dry. Either spray paint or standard liquid paint will work. Make sure you coat the entire line at least once.
Add a layer of rust-resistant paint. Once the primer is dry you have a layer of protection, but putting on rust-resistant paint gives your brake lines additional rust protection. Once that coat is dry, add at least one more coat of paint.
