Whenever you decide to disconnected the brake line, or alternatively if the master cylinder that you add brake fluid to gets too low, allowing air inside the lines, then you will have to bleed out the air from the brake lines. This is important because when air gets inside of the brake lines, it can lead to a pedal which skips or is mushy. Either of these is a perilous situation when an urgent stop is required. This article goes through the step by step directions to bleeding the air from the brake lines.
Materials Required for the Project:
- Twelve inch long rubber hose
- Crescent wrenches with closed and open ends
- Plastic container or bottle
- Goggles for your eyes
- Your car’s specific brake fluid
- Rubber gloves
- Old rags
Beginning with the Rear Wheels
First you will need to find the bleeder valve for your car’s breaks. These are located behind each wheel. The valve for each wheel is found on a part where the the rubber brake line hose connects to it.
Begin working at the rear wheels to start bleeding. Work forward towards the front wheels. You can bleed only one wheel, if you actually disconnected just one brake line. If you instead changed your master cylinder that feeds to all of the four lines, then you will have to bleed all of the wheels.
Working with the Bleeder Valve
You will have to loosen up the bleeder valve only enough to ensure that you do not have any problems with it. Now, re-tighten it immediately, so that no fluid comes out. If the nut will not move, you can always spray a little oil that penetrates rust on the nut and then leave it for a while. Next, take off the master cylinder cover and make certain that the brake fluid is full.
Positioning the Rubber Hose
Line your bottle and rubber hose up at the exact wheel on which you will work. The goal is to make sure that the brake fluid will run through your hose out of the bleeder valve straight into the bottle. This fluid can then be reused, so long as your container is clean.
Pumping the Brakes
For this step, you will need to find someone to sit in the car and turn the engine on. After you loosen up the bleeder nut only sufficiently for the fluid to start exiting, have the person pump the car brakes several times. The hose must be in place so that the fluid does not spray out everywhere. Your person inside the car will have to pump the brakes one more time, holding the pedal down as long as he or she possibly can. While this is being done, you have to rapidly tighten back up the bleeder nut. Now the wheel is finished.
Finishing and Cleaning Up
Return to the master cylinder. Fill the brake fluid all the way up. Either use new fluid, or the fluid which you captured inside of the plastic bottle. Your master cylinder should never run while it is too low or even dry, since then you will have more air back in the brake lines, requiring you to bleed all of the car’s wheels. Before you take the car on a brakes test drive, be sure to dry off all of the bleeder nuts with which you worked.
References:
Buzzle: How to bleed brakes
Mopar Magazine: How to bleed brakes
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