How to Repair a Rusted Brake Line

  • 2-6 hours
  • Intermediate
  • 50-100
What You'll Need
Line cutter
Socket wrenches
Line wrenches
Union fittings
Jack Stands or Service Ramp
Flaring tool
Hand protection (optional)

Keeping your brake line in good working order is a critical safety issue. A regular inspection is wise especially if you live in climates where your undercarriage is exposed to slush, snow and road chemicals. You may notice rust and corrosion on your brake line indicating that it is time to replace it.

Step 1 - Raise Your Car

In order to gain access to your brake line, you likely will have to jack up your car and place it on jack stands or drive your car onto car lifts. Follow all manufacturers directions and safety procedures for this step. Never work on your car with just the jack engaged.

Step 2 - Locate Your Brake Line

Your brake line goes along the inside of the car frame in plastic clips from the proportioning block to the front over the gas tank to the rear hose of the wheel cylinders. The brake line will be in slightly different locations in different cars. You can also check your owners manual

Step 3 - Remove the Brake Line

Trace the line to the proportioning block and using a line cutting tool remove the line. Using a line wrench remove the fitting. Trace the brake line to the rear hose of the wheel cylinder and remove it carefully from the brake line clips. Leave the manufacturers clips in place as you will re-fit the new line into them.

Step 4 - Buy New Brake Line

Brake lines come in pre-cut sections and will have to be assembled to create the same length as the one you removed. You will also need to buy union fittings to use as connectors.

Step 5 - Double Flare the Line

Before putting the flare on the line you need to slide the nut part of the connector over the pipe. The nut will later slide up the pipe to make the connection. If you fail to slide the nut on first you will not get it over the flare. Cut a clean straight cut at the end of the line and ream out any burrs with the reaming tool attached to your pipe cutter. Double flare the line using the double flare adapter in your flare kit. Detailed instructions are on the flare kit box on how to use this tool. A double flare is critical and you should never use a single flare in a brake line.

Step 6 - Connect the Sections

Connect the sections of line by mating the two sections and engaging the union connectors. The connectors will force the flared ends to seal.

Step 7 - Bend the New Pipe

Follow the same bend with your new line as the line that was removed.

Step 8 - Replace the Brake Line

Install the new brake line clipping it in to the manufacturers installed brake line clips. Attach the line to the brake hose at the wheel cylinder and at the proportioning block.