How to Repair Auto Hydraulic Brake Lines

The brake system in a car is the heart and soul of its safety features. Without properly functioning brakes, disaster is inevitable. Brakes use hydraulic pressure to force brake fluid into a wheel cylinder. The cylinder applies pressure to the brake rotor and pads, forcing the vehicle to stop. Repairing flexible brake lines can be done fairly easily, but in most cases for hard lines, it is easier to simply replace the entire brake line.

Instructions

1

Drain the brake fluid from the vehicle. There are two ways to do this. You can open the reservoir in the engine bay and siphon out the fluid. Or, you can remove the fitting on the brake caliper with an open-ended wrench and allow the fluid to drain. Let the fluid drain into a bucket and reinstall the caliper fitting if it was removed.

2

Use an open-ended wrench to remove the compression fitting at each end of the damaged brake line. Flexible brake lines are shorter and connect from a bracket to the brake calipers themselves. Hard lines are used along the length of the frame of the vehicle and connect the brake booster to the flex lines.

3

Remove the damaged brake line. This is the most difficult part of the procedure because of the location of some brake lines. Depending on the vehicle, manufacturers will place the brake lines inside the frame rails, between the frame and the body of the vehicle or in a tight crevice. Sometimes it is easier to leave the old line on the vehicle after you've disconnected it.

4

Travel to the auto store with a small piece of the old brake line. You will need a piece long enough to use as a reference for buying the new line and testing new compression fittings. The store employees should be able to help you identify the necessary pieces for your vehicle.

5

Attach the compression fittings to the new brake line. Use the brake line flaring tool to create the necessary lip on the end of the line and slide the fitting over top of the lip. This will create a vacuum tight seal for the brake line once it is installed. Repeat this step on both ends of the tubing.

6

Place the new piece of brake line into position. Use the open-ended wrench to attach the fittings at the front of the vehicle first. Position the brake line along the body and use zip ties to attach them to existing lines along the body. Attach the back end of the brake line in the same manner as the front.

7

Fill the brake reservoir with fluid. Remove the caliper fitting and have a friend pump the brake pedal to force all the air out of the lines. It will take several minutes of pumping to return full pressure to the line. Once a steady stream of fluid is coming out of the caliper, reinsert the fitting and tighten it down with an open-ended wrench. Repeat this step on any other brake line that was removed.