How To: Bleed Your Vehicle’s Brakes

How To: Bleed Your Vehicle’s Brakes

Hey everybody… Chris here from O’Reilly Auto parts to show
you how to bleed your brakes. It’s possible for air to get into brake
lines, and the result is spongy brakes. This can happen any time you work on a brake
booster or master cylinder, wheel cylinders or calipers, or any time the brake lines of
your vehicle have been open. Brake bleeding is necessary to remove the
air from brake lines. Today, I’ll be bleeding the brakes on this
2008 Dodge Nitro. The process will be similar for your vehicle,
but be sure to know the specifics before getting started. This includes knowing whether or not your
vehicle requires a scan tool in order for the brakes to be bled… some do. If you’re not completely comfortable doing
this yourself, we’d be happy to recommend a professional technician in your area. Before getting started, understand that brake
fluid is highly corrosive and should be handled carefully at all times and cleaned up promptly
when spilled. Make sure you read the first aid procedures
on the bottle before starting the procedure. First you’ll need to determine in what order
the lines will be bled. In most cases, it’s recommended you bleed
the brake line farthest from the master cylinder first and work back toward it. The position of the ABS system can affect
this, so always bleed the lines according to the manufacturer’s specifications for
your vehicle. In the case of our Nitro, we’ll go: right
rear wheel, left rear wheel, right front wheel, left front wheel. You’ll notice we’re starting with the
Nitro raised with the wheels off. For details on how to do this safely, see
our video on how to jack up your vehicle. Before you start, use a shop towel to wipe
down the master cylinder and cap to keep any contaminants from getting into the master
cylinder when you take off the cap. It’s a good idea to siphon most of the old
brake fluid from the reservoir… leave a small amount in the bottom. A simple siphon tool can be used for this. The old brake fluid will be dark-colored,
and the new fluid will be clear. Starting with new brake fluid in the master
cylinder ensures the fluid going from the master cylinder to the caliper or wheel cylinders
is new, fresh fluid. Check your owner’s manual for the recommended
fluid-change interval, and brake fluid type. Brake fluid should be changed regularly. And be sure to clean up any spilled brake
fluid immediately… remember, it’s highly corrosive. You can use the old, siphoned brake fluid
in the bleeding tool bottle. Once you’re done siphoning, top off the
master cylinder with new brake fluid, and put the cap back on. It’s important to make sure the master cylinder
never sucks air or runs dry… fluid should always cover the holes in the bottom of the
reservoir. And only use the brake fluid specified by
your vehicle’s manufacturer. Go to your first bleeder valve and remove
the cap… attach your box wrench… then attach the hose of your bleeder tool. We’ll be using a simple, one-person bleeder
tool to demonstrate this process. Situate the hose and bottle so that the hose
runs above the bleeder valve and down into the bottle… and make sure the end of your
hose is submerged in fluid before you open the valve. Turn the box wrench to open the valve… you’ll
see fluid starting to move into the hose. Inside the vehicle, push all the way down
on your brake pedal with slow, steady pressure. If you have a friend with you, have them apply
the brake pedal pressure… and close the valve again before the pedal is released each
time. The bleeder valve must be closed before allowing
the brake pedal to lift. Be sure your friend in the vehicle is clear
on when to let up on the brake. The brake pedal can be pumped to create pressure,
but only before the bleeder valve is open. Never pump the brake pedal with the bleeder
valve open. Repeat this several times… until there’s
no air in your hose and the fluid is looking more like the new fluid from the master cylinder. If you’re doing this by yourself, apply
that slow, steady pressure to your brake pedal several times… and check your hose for air
and fresh brake fluid. Once there’s no air in the hose and the
brake fluid looks clean, close the bleeder valve… and carefully remove the hose, letting
the excess fluid run into your bottle. Put the cap back on the bleeder valve, and
move to the next one. It’s a good idea to fill the master cylinder
reservoir before doing each brake line. During the process of bleeding, be sure to
check the fluid level in the master cylinder every few times the brake is pushed in…
and continue to add brake fluid as needed. Any time you’re not adding brake fluid,
leave the cap on the master cylinder. Also, keep an eye on the amount of fluid in
your bottle to make sure there’s enough room for each bleed… but enough fluid to
keep the end of your hose submerged. Once you’ve repeated this process at all
four brake lines, fill the master cylinder to the max line… and tighten the cap. After bleeding your brakes, always be careful
the first time you drive to make sure the brakes are working properly. If there’s still air in the lines, the brake
pedal will be spongy. If you have rear brake shoes, you may need
to adjust the brake shoes in order to affect the position or sensitivity of your brake
pedal. And that’s it. You’ll find everything you need for this
and other jobs at your local O’Reilly Auto Parts store or Our DIY videos are designed to help answer
questions we get in our stores every day. If you found this one helpful, subscribe to
our channel to get all the latest. We’ll see you again soon.

About the Author: Michael Flood


  1. You lost me at "we'll be using a one-person bleeder tool" followed up by "close the valve again before the brake pedal is released". Not possible with only "one person".

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