How to Fix a Broken Brake Line

by Don Bowman

A broken brake line is much more common in severe climatic zones, where it is subjected to corrosive salt used on the highways to melt ice. The corrosion, once started, can be a serious problem considering the consequences. When this situation is encountered, the entire brake system should be inspected. There are two methods for correcting this corrosion--one for lines exhibiting extensive deterioration and another for local problems.


Raise the vehicle and support it safely on jack stands.

Assess the extent of damage and determine how much of the brake line to replace. Check all sides of the brake line for corrosion. Check the flexible brake lines for evidence of leaking. Flexible brake lines are not repairable; they must be replaced. Make a list, if necessary, of parts needed.

Measure the length of the brake line to be replaced. If the problem is isolated to a particular area due to physical damage, measure the length of brake line needed to replace the affected area plus 6 inches.

Replacing an Entire Brake Line

Spray the connections with rust penetrant. Remove the brake line fittings with a line wrench.

Bend the new brake line, using the tubing bender, to match the old brake line. Lay them side-by-side for comparison.

Install the brake line and tighten the fittings with the line wrench.

Replacing a Section of Brake Line

Remove the section of brake line to be replaced using the tubing cutter. Lay the old brake line on the floor and measure it. Cut the new brake line 1/2 inch shorter to compensate for the compression fittings.

Push the cap for the compression fitting onto the brake line and move it up the line 2 inches.

Slide the ferrule, which looks like a ring, onto the line. Take the barrel part of the compression fitting and push the end of the brake line into it as far as possible. Pull the cap down toward the barrel, which will also move the ferrule down at the same time. Hand-tighten the barrel's cap while keeping pressure on the line to keep it in the barrel as far as possible. Use a wrench to hold the barrel while using a line wrench to tighten securely the cap to barrel. Repeat Step 3 for another compression fitting on the other end of the line.

Install the caps and ferrules (as explained in Step 3) on the ends of the brakes lines on the vehicle. Install the new brake line between the two cut ends of the existing brake line. Make sure to push the new brake line barrel fitting into the existing brake line while the caps are hand-tightened. Once both ends of the brake line end caps are hand-tightened, use the wrench and line wrench to tighten the end caps securely.

Bleeding the Brakes

Fill the master cylinder with brake fluid.

Loosen the brake bleeder screw on the right rear brake and leave it open until it has a steady drip, indicating it is full of fluid. Do the same for the left front, then the left rear and finally the right front. Check the brake fluid each time a brake is bled.

Check the entire line for leaks. Fill the master cylinder as needed.


  • close Start the car and, while still in park or neutral (in the case of a stick shift), pump the brakes until they feel "normal" again. The brake pedal may or may not be "low" after doing this job.

Items you will need

About the Author

Don Bowman has been writing for various websites and several online magazines since 2008. He has owned an auto service facility since 1982 and has over 45 years of technical experience as a master ASE tech. Bowman has a business degree from Pennsylvania State University and was an officer in the U.S. Army (aircraft maintenance officer, pilot, six Air Medal awards, two tours Vietnam).