Bleeding Brakes Is an Intermediate Job for Most DIYers. Here’s Everything You Need to Know to Change Brake Fluid at Home.
- DIY Difficulty Level: Intermediate
- Time Required: 1 to 2 hours
- Tools & Materials:
- Brake fluid
- Jack and jack stands
- Wrenches
- A short length of clear tubing
- A small bottle
- A helper
What Is Bleeding Your Brakes?
Your brakes operate on a hydraulic system. Pressing the brake pedal pushes fluid through lines to your calipers, which press the pads against your rotors to slow or stop your car. Over time, this fluid absorbs moisture and gets dirty, which reduces its effectiveness.
Bleeding your brakes is the process of pumping old fluid out of your master cylinder, brake lines, etc. and replacing it with new, clean fluid. This differs from a brake fluid flush in that it does not replace all of the old fluid in your brake system, only in the main components. Your anti-lock braking system also contains fluid, but it is not possible to flush your entire brake system without specialized equipment that typically only mechanics have. Bleeding the brakes yourself will change out most of the fluid, though, and is often adequate.
Is It Safe to Drive with Old Brake Fluid?
Over time, your brake fluid can absorb moisture. It can also get dirty, which causes the fluid to turn from a nice clear liquid to brown in color. If your brakes get too hot from constant braking down a steep hill, the fluid can boil, introducing gas into what is supposed to be an airtight system.
Any of these conditions reduce the effectiveness of your brakes. You may have to push the pedal harder to get the desired braking performance. Eventually, you may not get as much braking power as you need. You also won’t be able to stop as quickly as you should, which is a safety concern.
The beauty of your brake system is that since it absolutely has to work, it’s very simple, with few parts that can go wrong. If you’re mechanically inclined and comfortable working on your brakes, you can do this job at home. It only costs $74 to $94 to have a professional do a complete brake flush, though, so if you have any hesitation about doing this yourself, take it to the shop to be sure.
When to Bleed Brakes
Generally speaking, it’s best to flush your brake fluid every two years or so. If you are particularly hard on your brakes, such as if you drive at track days, you should bleed your brakes at least twice a year, if not before every event. If you do a lot of driving in mountainous territory, bleed your brakes once a year. That’s hard on brakes, too, but not as hard as the extremes of a race track.
What Are Common Symptoms Indicating You Need to Bleed Your Brakes?
- Brake pedal feels soft
- Brake pedal goes all the way to the floor
- Reduced braking performance
- You may have to “pump” the brakes to get full braking power
Keep in Mind
Check your owner’s manual and consult the maintenance schedule to see how often the manufacturer of your car recommends flushing the brake fluid. Some manufacturers have no recommended schedule. If that’s the case, follow the guidelines mentioned above.
Make sure you use the same type of brake fluid as specified in your owner’s manual (usually DOT 3 or DOT 4, and occasionally DOT 5). The brake fluid reservoir cap will also usually tell you which fluid to use.
The following services are commonly performed with a brake fluid flush:
- Disk brakes: Check or replace brake pads and rotors
- Drum brakes: Check or replace brake shoes and drums
- Check calipers and wheel cylinders, replace if necessary
- Now is an excellent time to rotate your tires, since they’re all coming off the car anyway.
How It’s Done
Before you begin, make sure you have a helper available. The actual process of bleeding the brakes requires two people. Watch the video then follow along with the steps below!
Step 1: Jack up your car
Follow these instructions to jack up your car and support it on jack stands. If possible, lift the entire car off the ground using four jack stands. If you only have two, start with the back of the car.
Step 2: Remove the wheels
This job is easiest if you take all of the wheels off the car. Again, if you only have two jack stands, do the rear first, then move to the front later.
Step 3: Loosen the bleeder screw
Starting with the right rear corner, find the bleeder screw. This is a screw in the caliper or wheel cylinder that has a nipple on the end. Carefully loosen it, just to make sure it’s not seized. (If it is, it’s better to find out now than later.) Slip a piece of clear tubing over the nipple and drop it into your bottle to catch the brake fluid as you pump it out of the car.
Step 4: Top off your brake fluid
Open your hood and locate the brake fluid reservoir. Open the cap, and fill it to the top with new brake fluid. It’s okay to go past the “full” line right now because the level will drop as we pump old fluid out of the system.
Step 5: Pump the brakes
This is where you’ll need your helper. Have them sit in the driver’s seat while you go to the right rear wheel. Repeat the following steps, in this precise order:
- Open the bleeder screw.
- Have your helper push the brake pedal all the way to the floor, and hold it there.
- Tighten the bleeder screw.
- Have your helper release the brake pedal.
The order of these steps is critical so that brake fluid comes out, and no air gets into the brake lines when your helper releases the brake pedal.
Keep repeating these steps to pump the old fluid out of the lines. Watch the fluid coming out. You may see air bubbles, or the fluid may be dark. That’s why we’re pumping it out. Repeat the pumping process until you see new, clear fluid coming out instead of the dark old fluid. The right rear corner will take the longest time, since you’re bleeding not only the longest brake line on the car, but also the contents of the master cylinder.
When you’re done, tighten the bleeder screw and remove the tubing.
Step 6: Top off your brake fluid
Add more brake fluid to the reservoir to replace what you pumped out of the system. You may want to check this part way through bleeding the right rear brake because this takes a while. Under no circumstances do you want to let this reservoir go empty. This will suck air into your brake lines, which you’ll have to pump out and start over again.
Step 7: Repeat for the remaining brakes
Repeat steps 3 through 6 for the other brakes on your car. Do them in the order of the longest distance to the master cylinder to the shortest. After the right rear, move to the left rear, then the right front, and finally the left front.
If you’re only using two jack stands, when you’re done with the rear brakes, put the wheels back on and lower the car to the ground. Then lift and support the front of the car, remove the front wheels, and continue the process.
Step 8: Fill brake fluid reservoir to “full” line
After bleeding all four corners of the car, top off the brake fluid once again. This time only add fluid until the level reaches the “full” line on the reservoir.
Step 9: Start the engine and test the brakes
You don’t need the engine running to bleed your brakes, but when you’ve done all four corners of the car, start the engine and give the brake pedal some good hard pushes. It should feel firm, not soft or squishy, and it shouldn’t go all the way to the floor. If this is not the case, go back and make sure you’ve tightened all of the bleeder screws and that brake fluid isn’t leaking out. If the pedal is still soft, you may have introduced air into the brake lines while bleeding them. Repeat the bleeding process for all four brakes. It’s a bummer, but it’s better to find out now than when you’re driving down the road and need to stop.
Step 10: Install the wheels and lower the car
Now is a great time to rotate your tires if you need to.
Step 11: Take a test drive
Go for a quick spin to make absolutely sure the brakes are working properly. Start gingerly on the brakes, and work your way up to a few hard stops to make sure they can take it. Be prepared — your brakes will likely work much better than they used to!
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Recovering autocross and track day enthusiast. Once turned a VW Jetta into a pickup truck. Lives in a van down by the river. Dream car: 2001 Subaru WRC rally car.
