When you hear the word bleed it oftentimes means something dangerous and gory, but when it comes to brakes, it means something quite the opposite. You should bleed your brakes every two or three years, flushing them oxidized brake fluid, for the safety of you and your passengers. You may need to bleed brakes if you replace a caliper or if there is a brake fluid leak. Air in the system robs your brakes of stopping power, and can be a dangerous situation. Bleeding brakes isn’t particularly difficult, but with the right tools and the following steps, we will have you bleeding your brakes like a pro. (Keep in mind that some newer cars may not respond to this method, particularly those with electro-hydraulic brake boosters instead of vacuum brake boosters, as they require scan-tool activation to properly flush the master cylinder.)
Brake fluid is literally the blood of your brakes and can mean the difference between stopping on a dime and not stopping, maybe never. This means, just like your own blood, your brake fluid must be working and in perfect health, for the safety of everyone in and around your car. The fluid, unfortunately, can become contaminated by dirt and other abrasive particles, and also absorb moisture, which can accelerate corrosion or even boil. These can lead to future issues and poor braking quality, so replacing your old brake fluid during the bleeding process may be a necessity.
- Using a couple brand new cans of brake fluid, you will want to properly bleed brakes with the car in the air and the wheels off. This can be done with the wheels on but you have to be sure you can attach a wrench to the bleeder valves.
- Once you are with the bleeder valves, you need to find out if you can loosen them. Using a box wrench, and avoiding the use of a crescent wrench or Vise-Grips, try to loosen the bolts. You may need some penetrating oil and a hammer to motivate the valve into loosening, but keep the bleeder valve closed for now. If you can’t remove the bleeder valves, without breaking them, then you will need to replace you brake calipers or wheel cylinders, adding an additional headache to the process. This may be the time to call the professionals.
- If you were successful in loosening all four bleeder valves, move on to the master cylinder reservoir. You will need suction gun or similar tool, such as a turkey baster (but don’t put it back in the kitchen drawer when you’re done), to suck out the old fluid from the master cylinder reservoir. Use a rag to clean out any leftover sediment from the reservoir, making sure not to drip the brake fluid anywhere.
- Using a clear piece of plastic tubing, put one end of it over the recently loosened bleeder valve on the right rear brake caliper or wheel cylinder (that is, the passenger side rear brake), and put the other end into a bottle with an inch of new brake fluid in it. Make sure the tube stays below the level of the fluid, to keep air from drawing back into the system. Put a small block of wood under the brake pedal to prevent it from going all the way to the floor, which could damage the seals in the master cylinder. Add brake fluid into the master cylinder, as you want to ensure no air gets into the system again.
- You will need a friend for the next step, someone you can trust implicitly to follow instructions. Have them sit in the driver’s seat, listening to your commands. You will tell them to press in on the brake, with enough force to bring your car to a stop, if you were out driving it on a roadway. Let them know that the pedal will sink, and they need to continuously put pressure on it.
- You should see the old fluid start bleeding into to the bottle. When it stops, close the bleeder valve and let your friend know to lift the pedal. Keep following this process, watching for new fluid to start coming out. Do this on each wheel and it is extremely important for you to keep the reservoir full during this, to keep air out. Do not let it get below halfway.
- Repeat bleeding brakes, continuing on the left rear (driver side rear brake), then right front (passenger side front brake), and finishing with the left front (driver side front brake). Finally, top off the brake master cylinder reservoir with fresh brake fluid to the “FULL” marking.
If you stick to these steps to bleed brakes on your vehicle, you will be well on your way to achieving, yet another, impressive DIY victory.