How to Repair a Rusted Brake Line

by Don Bowman

There are two ways to repair a rusted brake line and it all depends on how much of the line is rusted and where. If the vehicle has been up north and the salt has gotten to it to the extent that most of it is rusted, the whole line should be replaced. If, by chance, there is just one section, such as the area running between the wheel along the frame, then replacing just a piece would be the easy, safe solution.

Look the line over for the extent of rust. If the line has anything more than surface discoloration it should be replaced. If it is all rusty, measure the length of the line from one end where it is attached to the other. Always add a foot for error when bent and for cutting. If the entire line is to be replaced, after measuring, soak the fittings to be removed with penetrant for about 15 minutes. It may be necessary to soak them several times to get them out.

Use the sockets and ratchet to remove all the brackets holding the brake line to the frame. Each bracket has one screw.

Using the line wrenches, remove the brake line fittings if you are replacing the whole line. If you are replacing one section, then cut the section of the line out with the tubing cutter. To use the tubing cutter, put it around the line and tighten the screw. Rotate the cutter one turn and further tighten the screw. Continue this process until the line is cut.

Lay the old brake line on the floor. Use the tubing bender and make the new brake line have the same bends as the old one. When the brake line looks the same as the rusted one, attach it to the vehicle using the line wrenches to tighten the fittings. Replace the hold-down brackets to keep the line in place.

Cut any excess brake line using the tubing cutter as before. Take the compression fittings apart. There will be two end caps with a hole in the center for the line, two ferrules that resemble a wedding ring, and a center tube with threads on both ends. Place one of the end caps on the line. Place the ferrule over the end of the line. Hold the center tube or barrel in one hand and the line with the cap and ferrule in the other. Push the line into the barrel and screw the cap onto the barrel--it will collapse the ferrule around the line and lock the line into the barrel with a leak proof seal. Hold the barrel with one wrench and tighten the end cap with a second wrench.

Place the other cap and ferrule on the cut line on the vehicle. Push the new line with the ferrules and caps onto the old line. While pushing, draw the cap on the old line tight on the barrel. Now it is in place--do the same for the other side.

Fill the master cylinder reservoir with brake fluid. Bleed the brakes with a helper. Start the car and loosen the brake bleeder screw on the passenger rear wheel. Tell the helper to push the pedal to the floor and hold it there. When the pedal is to the floor, close the bleeder valve. Now tell him to let the pedal up. Repeat this process until nothing but fluid comes out of the line--no air. Do the passenger rear and then move to the driver's rear, then passenger front and driver's front.

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).