In a previous article, we covered the process of changing power steering fluid with the help of a simple turkey baster. When preparing for a brake fluid flush last summer, we considered purchasing a fancy evacuation pump designed to pump out the old brake fluid. As we pondered the process a little further, we elected to use a handy turkey baster to remove the old brake fluid and then conducted a standard brake bleeding procedure.
Why Change Brake Fluid?
Like any other automotive fluid, brake fluid degrades and deteriorates over time. But what is even worse is that brake fluid attracts moisture and this happens even in a sealed system. As brake fluid absorbs moisture, it loses its high temperature resistance and also starts to promote rust and corrosion. Brake fluid should be changed every two years, even if you don’t put big miles on your vehicle. If you haven’t changed your fluid for several years (or ever), you will note the old fluid comes out looking like Coca-Cola, while the new fluid will have a clear or light amber appearance.
Items Needed for a Brake Fluid Change
- The correct grade of brake fluid (DOT3, DOT4 or DOT5) as prescribed by your owners manual or the cap on your brake reservoir.
- Turkey baster for drawing out old fluid from the brake reservoir.
- About 4 feet of clear plastic or rubber tubing with a ¼” inner diameter.
- An empty plastic soda pop bottle with a hole drilled in the cap, allowing the hose to fit tightly through cap.
- A jack with sufficient capacity to raise your vehicle, along with jack-stands and blocks.
- An assistant to manage the brake pedal.
- The correct box-end wrench to open and close bleeder screws.
- Be sure that you have jacks, jack-stands and blocks that are capable of safely raising and holding your car or truck.
- Brake fluid is corrosive to painted surfaces. Be sure to protect any areas that could be exposed to accidental contact.
- During the bleeding process, never let the brake reservoir empty out as the system can draw air.
Raise All Four Wheels or One At a Time?
If you are not comfortable with having all four wheels off the ground, you certainly can bleed the brakes of each wheel separately. It is better to have one wheel elevated safely, then to have all four wheels up in a precarious fashion.
How To Change Brake Fluid
Step 1. Raise and remove at least one wheel. When bleeding brakes, work your way from the wheel farthest from the fluid reservoir and end with the brake-set closest. Generally the furthest wheel from the reservoir is the rear passenger side wheel.
Step 2. Using the turkey baster, remove old brake fluid from the reservoir until it is as empty as possible. Note that the filler neck on some reservoirs is offset, making it impossible for the baster to reach the fluid. In these cases, all of the old fluid will have to be removed through the bleeding process. This can be more time consuming, but it is certainly doable.
Step 3. Fill reservoir with fresh fluid to the “Full” marker and leave the cap loose on top of the fill hole.
Step 4. Lubricate the threads of the bleeder valve on the brake caliper. Fill the pop bottle with a few inches of fresh brake fluid. Attach cap and feed the hose through the hole in the cap into the bottle so that the end of the hose is submerged in the fluid. This prevents air from draining back into the system during the process. Place the appropriate box-end wrench on the valve and attach the other end of the hose to the bleeder valve.
Step 5. With your assistant operating the brake pedal, open the valve and have them slowly press the brake pedal. As they reach the bottom of the stroke, close the bleeder valve. The assistant can then release the brake pedal once the bleeder is closed. You will note the old fluid and air bubbles in the hose as the brake pedal is pressed.
Communication is important during this process. Make sure that your assistant is not releasing the pedal while the bleeder valve is open.
Step 6. Repeat step five until fresh fluid and no air bubbles are visible in the hose.
Important: As mentioned, regularly monitor the fluid level in the reservoir and top-up as necessary.
Step 7. Perform this process on each brake assembly, top-up the reservoir one final time and you are done.
A brake fluid flush can be performed with no special tools or pumps. Do this every couple of years and enjoy the peace of mind knowing that you’ve done your part to optimize the performance and reliability of your braking system.