Your brakes are the most important part of your car, so why not make sure the job is done right by doing it yourself?
Knowing how to bleed your own brakes will save you from spending way too much money at the dealership for a job that you can do yourself.
Learning to bleed your own brakes will open so many DIY doors, you’ll be keeping your car tip-top in no time!
In this guide, you’ll learn:
- Why brakes need to be bled?
- The best ways to bleed brakes
- Equipment required to bleed brakes
- How to perform a brake bleed, step by step
Why Do You Need to Bleed Air From the Brakes?
When you press the brake pedal, the pressure forces brake fluid through the brake lines and operates the brakes at the wheel.
If your brake fluid has air in it, the pressure will compress the air instead of moving the fluid, and your brake pedal will go to the floor but the car won’t slow…
That’s why it’s so important to bleed any air from your brakes, so that won’t happen while you’re driving!
When Should You Bleed Your Brakes?
Air must be bled from your brake fluid any time the system was opened, allowing air to get in.
The most common times you’d bleed air from your brakes is after replacing any parts that use brake fluid: brake calipers, hoses, brake lines, or the brake master cylinder.
It’s less common, but you may have to bleed your brakes if you’ve felt the brake pedal get squishy over time. This means that there’s a slight leak that’s letting air into your brake fluid.
Leaks may be caused by a cracked brake hose, a leaking master cylinder, or a bad fitting, but no matter the reason, your brakes will lose efficiency or stop working completely if the air isn’t bled out.
How Do You Bleed your Brakes?
There’s basically two ways to bleed your brakes:
A Two-Person Operation:
One will pump the brake pedal while the other opens and closes the brake pedal. This method is good to know as a backup plan, but it’s a bit outdated for today’s standard
A Brake Bleeding Kit:
This is the method I recommend because it’s quicker, the kit has almost everything you need, and you can do the job yourself.
What Are The Benefits of Using a Brake Bleeder Kit?
Bleeding the air out of your brake fluid can be an arduous process, usually requiring two people and a couple hours. A brake bleeder kit makes the process quicker, cleaner, and you can do it alone!
Knowing how to use a brake bleeder kit will save you time and frustration whenever you replace brake calipers or cables, or flush the fluid.
Once you are confident servicing your own brakes, you’ll be saving money on dealership labor costs and avoiding all-too-common auto shop scams.
What Do You Need To Know About Using a Brake Bleeder Kit?
This is the number one piece of advice I give to people about bleeding brakes:
It’s not complicated. Once we get into all the details of each step it may seem complicated, but remember it’s not.
It’s as simple as pressurizing the brake fluid, opening the bleeder screw to let the old fluid and air come out, then closing the bleeder screw.
What Supplies Do You Need for a Brake Bleeder Kit?
The kit should include all the hardware you’ll need:
- Bleeder kit AKA vacuum pump with a pressure gage
- At least two brake hoses (included with bleeder kit)
- A wrench that fits your bleeder screw
- Big bottle of brake fluid
I usually grab the 32oz bottle of brake fluid because you won’t know exactly how much you need, and it’ll be a giant hassle if you run out before the job’s done.
Most street cars use DOT 3 brake fluid, but consult your owners manual and assess your needs.
What Are The Different Ways to Use a Brake Bleeder Kit?
There are a few ways to use a brake bleeding kit, depending on which kind you buy.
There’s the very basic kit, which just comes with hoses and adapters. I don’t recommend this kit because it relies on the two-person method we talked about earlier.
This method is fine as a backup plan, but it’s not the best option these days.
Another type of kit you might see is a compressor bleeding kit. These are actually the least work, in theory, but I don’t recommend them because these kits require too much extra, expensive equipment.
To use this kit you have to own an air compressor with air hoses, all which don’t come cheap, and the bleeder alone can cost eight-times more than a hand pump.
My recommendation is a standard one-person manual pump bleeding kit. For most home mechanics and DIYers, this will fit your needs best because it’s cheap, portable, and gets the job done without hassle.
This kind of kit is also the most common kit you’ll find, so this will be the type I’m referring to as we break down the step-by-step guide below.
How To Use a Brake Bleeder Kit (7 Steps)
Step 1: Lift car and remove wheels
When bleeding brakes, start with the wheel farthest from your brake master cylinder. For most American cars that means starting with the passenger back wheel, then driver side back wheel, then passenger front, and finally the driver side front wheel.
Jack the rear wheels off the ground and place the vehicle securely on jack stands properly rated for your car. Consult your manual for your car’s reinforced jacking point.
If you’re not certain you know how to jack up a car correctly, check out this video. Better safe than sorry!
Remove the wheel by unscrewing all lugnotes and storing them somewhere safe. Your brake caliper or drum should be exposed and ready to bleed!
Step 2: Clean debris
Now that our brakes are exposed, let’s quickly locate the bleeder screw. The bleed screw is usually located on the back of a brake caliper or drum, it has a shiny metal tip and a hex-shaped base for the wrench.
Once you’ve found the bleeder screw, grab a lint free rag and clean any debris on or around the screw.
While we’re in a cleaning mood, let’s wipe any dirt and grime around the brake fluid reservoir, usually located in the back right corner of the engine bay.
(NOTE: do not open the cap until we’ve cleaned any nearby dirt. It’s very important not to introduce debris that will compromise the braking system.)
Step 3: Top off brake fluid
Use the fresh brake fluid to top off your reservoir. The level will drop as we bleed the brakes, so it’s fine to fill it a little past the “full” line.
(NOTE: brake fluid is highly caustic, clean any spills immediately and keep away from children or animals!)
It’s very important that our brake fluid reservoir doesn’t get too low while we bleed the brakes. Check the fluid level often, if it gets too low it could suck more air into the system.
Step 4: Assemble the brake bleeder kit
Check your kit instructions to confirm your model’s assembly, but in my experience they assemble basically like this:
Start by attaching your brake hoses to the reservoir that came with the kit. The reservoir should have an inlet and an outlet–slide one hose over each.
With the opposite end of one hose, attach to the hand pump, and press the opposite end of your second hose over the brake bleeder screw.
Now you should have a series of hoses connecting your pump to the brakes, all fit snugly to avoid leaks.
(NOTE: depending on the size of your brake bleeder screw, your brake fluid hose may not fit snug. If this happens, fear not. Just find the plastic adapter in your kit that fits snug enough to create a seal.)
With all your fittings in place, it should create a tight seal capable of creating negative pressure with the pump. Test your seal by pumping to -10InHg (Inch of Mercury, the unit of measurement on most bleeder kits.)
If the system creates negative pressure and the gage holds at that number without dropping, then congratulations because you’re ready to bleed your brakes!
(If you’re not building negative pressure, or the gage drops, that usually indicates one of your hoses is leaking. Try reassembling and checking all fitments are tight. A ziptie tightened at the end of your hose can help fix leaks, if needed.)
Step 5: How to bleed
Finally, the step we’ve been waiting for: how to use your kit to bleed the brakes.
With the bleeder screw closed, pump the system to -25InHg. Your system has created a vacuum, so now take your wrench and turn the bleeder screw counterclockwise slowly.
You should see the pressure drop as brake fluid and bubbles are pulled into the hose. When the pressure gage drops to -5InHg, close the bleeder screw and pump it back to -25InHg, then open the bleeder screw again.
Repeat this until you aren’t getting bubbles. For reference, the reservoir from your kit may fill to 2-3 inches of old brake fluid.
Don’t forget to keep an eye on your brake fluid reservoir under the hood, refill as needed.
Step 6: Repeat
Repeat the bleed process on the three remaining brakes in the order from step 1.
Step 7: Test
Once all four brakes have been bled until all the bubbles–or nearly all–have stopped, it’s time to do a quick test. Hop in the driver seat and firmy press the brake pedal.
If all the air has been bled, the pedal will feel solid and firm.
If there is still air in the line, the pedal will have a soft, malleable feel to it.
If this is the case, you may need to try bleeding again, or search for a leak in your brake lines where air is getting in.
My Final Thoughts on How to Use a Brake Bleeder Kit
Bleeding brakes may feel intimidating the first time, but there’s nothing to it. The worst mistake you can really make is letting more air in, and that just means more practice bleeding!
Take it slow, review each step carefully, and you’ll have your brakes working tip-top in no time.
Once you’ve got the equipment and the know-how, you’ll be saving money on expensive labor costs, and you’ll have more confidence in the safety of your car knowing that the job was done right.