How to Bleed Car and Truck Brakes

Anytime a brake line is opened or a hydraulic part is replaced, air can enter the brake system. The process of break bleeding is quite simple. Opening the bleeder valve at the calipers or wheel cylinders on older vehicles, allows you to bleed air or flush fluid from the brake lines replacing the air with fluid. 

When there is air in the break system and you step on the brake pedal, the trapped air compresses causing the pedal to travel farther than normal. Instead of a firm pedal it feels soft and spongy. If there is a lot of air in the system the pedal will go all the way to the floor without applying the brakes. Pumping the breaks pedal may stop the vehicle but the amount of breaking action you get may not be sufficient to stop the vehicle. Bleeding the breaks will get all the air out of the system. This will restore the breaking system to a normal operation.

Manually bleeding the brakes pushes fluid through the lines and removes the air in the process. . It does require two people, a helper to pump the brake pedal while you open and close the bleeder valve.

How to Bleed Car and Truck Brakes:

1. Jack the vehicle off the ground and set it on jack stands. Never get under a vehicle if it is not on jack stands. Remove all four wheels to gain access to the break bleeder valves located on the brake calipers.

2. Remove the top of the master cylinder reservoir.

3. Insure that the master cylinder is full of brake fluid. 

4. Replace the top of the master cylinder reservoir.

5.  Attach a clean piece of clear plastic hose to the bleeder port and run it to a small container that has a couple of ounces of brake fluid in it. This will prevent air from back feeding into the system when you open the bleeder valve.

6. Have your helper slowly depress the brake pedal with an even force and hold it down.

7. Starting with the rear passenger wheel, open the bleeder valve about a quarter turn. Fluid and air will pass through the tubing into the bottle. When the fluid stops or when the brake pedal travels all the way to the floor, close the bleeder valve.

8. Have your helper remove his foot from the pedal allowing it to move up.

9. Repeat this process until clear fluid comes from the bleeder tube. Insure that the bleeder valve is closed before your helper removes his foot from the pedal. If required top off the master cylinder reservoir with fluid after each wheel is bled. If the reservoir fluid gets too low, air will be sucked into the master cylinder.

10. Tighten the bleeder valve.

11. Repeat this process on left rear wheel and then on the left front and right front wheels. If there is a lot of air in the system this process may have to be repeated several times.

12. Reinstall the wheels and lower the vehicle to the floor.

13. Road test the vehicle.

That is all there is to it! Bleeding car and truck brakes is not a difficult task buy it can be a little messy. Insure that you properly dispose of the waste brake fluid and dirty rags.

Related articles: