How To Change Your Vehicle's Brake Fluid In 5 Steps

Posted on: 20 October 2014

Your brake system is your vehicle's most effective safety feature. To ensure that your brakes always work, you've performed timely brake pad and rotor replacements. Although it's important to replace these components at regular intervals, your brakes may still operate poorly if you don't flush and replace your brake fluid as well. By following these five steps, you can replace your brake fluid in just a couple hours:

Purchase Replacement Brake Fluid and A Bleed Kit

Every vehicle's brake system is designed differently. Heavy vehicles, such as sport utility vehicles or trucks, require powerful brake systems that can tolerate extremely high temperatures. Lighter vehicles, such as compact cars or sedans, only require moderately-powerful brake systems. For this reason, these vehicles typically require different grades of brake fluids.

If you're not sure what type of brake fluid your vehicle requires, then consult your owner's manual. Some vehicles also have their brake fluid specifications listed on the cap of their brake fluid reservoir. If you aren't able to determine what type of brake fluid your vehicle requires after checking these sources, then talk to an employee at the auto supply store from which you plan to purchase your replacement brake fluid.

In addition to replacement brake fluid, you'll also need a siphoning tool to pull your worn brake fluid out of your brake lines and master cylinder. You can find a brake bleed kit containing everything you'll need at your local auto supply store. Bleed kits contain a bottle, pump, and acrylic tubes.

Prepare Your Vehicle

To prepare your vehicle for a brake fluid change, raise it off the ground using a hydraulic floor jack and jack stands. Make sure to place your jack stands underneath your vehicle's safe lifting points.

With your vehicle suspended, remove your tires and set them aside. Make sure you remember where each tire was installed—if you reinstall your tires on different wheel assemblies, then you may alter the alignment of your vehicle.

Bleed Your Brake Lines

Each of your brake assemblies will have a small bolt or plug—called a bleeder valve—on their interior sides. You'll need to open each of these valves with a pair of vice grips or a wrench. Once each valve is opened, you can connect your bleed kit to the valve and begin siphoning your brake fluid. However, you must bleed each of these lines in a specific order.

Begin the bleeding process at the brake assembly that's furthest away from your master cylinder. Continue draining the brake lines that are furthest away from your master cylinder until all four of your brake lines are cleared of old brake fluid.

For example, if your vehicle's master cylinder is installed on the driver's side of your engine bay, then the bleeding process must begin at the brake assembly on your rear passenger wheel and end at your front driver's side wheel. By performing the bleeding process in this order, you can ensure that all old brake fluid is completely removed from your brake system.

While bleeding each of your brake lines, continually refill your master cylinder with your replacement brake fluid until your brake fluid settles at the fill line. Remember to reinstall your reservoir cap each time you pour in new brake fluid to avoid letting air into your brake lines. If you allow air to get into your brake lines, then your vehicle will develop a sponge-like brake pedal.

Stop bleeding each brake assembly when you see clean brake fluid flowing through your kit's acrylic hoses. When you finish bleeding each line, remember to close the bleeder valve by tightening it with a wrench or vice grips.

Pump Your Brake Pedal

After you bleed your brake lines, you'll need to pump your brake pedal a few times to allow your master cylinder to work your new brake fluid throughout your entire brake system. Pump your brake pedal about 10-15 times or until it feels normal.

Test Your Work

Slowly test drive your vehicle around your neighborhood street. If you replaced your brake fluid correctly, then you'll experience a drastic improvement in braking performance. However, if you failed to remove all the old brake fluid from your lines, or didn't completely refill your master cylinder, then you may experience issues with your brakes while driving your vehicle. If you aren't able to fix any issues that you encounter, then take your vehicle to your mechanic for professional brake service.