We are a team of ASE certified mechanics that have created this ABS brake
bleed service guide to help you save money or at least see what you are paying
for when having the job done.
What Goes Wrong?
When doing brake service work air can get trapped inside the system causing
the brake pedal to go to the
floor or be spongy. ABS brake systems can be especially tricky because air
can become trapped inside the ABS controller valves which under normal bleeding
procedures will not remove. Moisture also plays a part in the requirement of a brake bleed or flush. In the normal operation of the
brake system moisture is created in the form of condensation when the brakes are
heated and then cooled. Rust will then form which will create pits in the
caliper/wheel cylinder piston or cylinder bore which will cause leaks and bypass
the rubber seal eventually causing a leak.
How Much Does It Cost?
When having a simple brake bleed done at a repair garage or the dealer it
will cost about 1.2 to 2.0 hours of shop time. If you are doing a brake bleed
yourself the cost will be a small amount of brake fluid or about $5.00 dollars (US).
Let's Jump in!
Most of the time a normal brake bleed will be sufficient to return the
brake pedal to normal operating conditions, but occasionally air will get
trapped inside the ABS module control valves. We will cover the normal bleed
and further down (bottom) in this guide the ABS version which includes opening the
ABS control valves which will purge the remainder of the air. Start with the vehicle on level ground. Engine off and the
car lifted safely using jack stands.
Before we begin fill the
cylinder completely while avoiding spillage, if you do accidentally have
a spill quickly use soap and water to rinse the area clean, add only
manufacturer recommended fluid.
Before opening the master cylinder use a shop towel to wipe it clean.
This will help keep dirt out of the reservoir which can cause seal failure by contaminating the fluid.
Grasp the lid and twist counterclockwise to remove it. Some lids have a
fluid level sensor that has wires attached which you can pull directly upward. Once
removed, wipe off any excess fluid and set it off to the side.
When adding brake fluid you may need to use a funnel to aid in the
process, continue adding until the fluid reaches the full line and then
remove the funnel. Most brake systems use a DOT 3 or DOT 4 fluid but if you
are not sure consult your vehicle's owner's manual or it will mention the
fluid type on the lid of the master cylinder. Reinstall the reservoir cap and wipe off an access fluid. You are ready to bleed the brake system.
Locate all four brake fluid bleeder fittings located near the top of
each brake caliper or wheel cylinder on each wheel which may have a dust cap
Using a small screwdriver or pick remove the bleeder dust cap and place it to the side to be reinstalled once the job is
Watch the Video!
This video features a brake bleed and flush, when finished read through
the remainder of the guide to glean additional information, the ABS bleed
video is further down.
Bleeder screws can be fairly tight, apply WD40 or equivalent to aid in
rust removal if needed and use a 6 point socket which is best to avoid
stripping. Once broken loose, place a boxed end wrench over the bleeder and
connect a rubber hose onto the bleeder and over the wrench. This hose is
helpful to avoid fluid from getting onto the pads etc,
access fluid should be hosed
off with water once the job is completed.
Now it's time to start the bleeding process. Have a helper push down on the brake pedal slowly and hold even pressure downward. Do not let up on the pedal.
When bleeding, never pump the brake pedal as this will cause additional air
to get into the system. (There is a very small orifice inside of the master
cylinder that allows new fluid down into the master cylinder chamber. If you
pump the brake pedal can cause air to be drawn backwards in through the
seals of the master cylinder).
Start with the left front and open
the bleeder valve while the opposite end of the rubber tube is in a fluid
Fluid will start to flow out of the bleeder and tube, bubbles will stream
out with the fluid if air is present in the system.
The brake pedal may travel downward, if the pedal goes to the floor
initially this means there is a bunch of air in the system, (the pedal will
return to normal height once the bleeding process is complete). Hold pressure on the pedal, as the
flow starts to slow down tighten the bleeder valve, (Do not let up on the brake pedal while the valve is
open or it will such air back into the system and you will need to start over).
Once the bleeder valve is closed, lift up on the brake pedal (slowly)
until your foot comes off of the brake pedal pad. Continue this process at
each wheel until fluid is present with no air bubbles being expelled from
the bleeder valve or hose, this can take two or three times. Now one corner
of the system is bled, continue this operation on the right front, left
rear, then and then finish with the right rear.
While bleeding the system, observe brake fluid level in the reservoir and
refill as needed to keep the master cylinder full. Do not allow the master to
become empty or air will be pumped into the system and the
master will need
to be removed and bleed unless a power bleeder is used.
Once the job is done refill the brake fluid to the full line of the reservoir and reinstall the lid.
Use a shop towel to wipe off any spilled fluid and rinse the area with water if needed.
Then start the engine and check brake pedal operation which should be firm and
at the top of its travel. If the
brake pedal is on the floor or spongy there is
air still in the system or another problem. This could mean the brake shoes are out of adjustment
or the master cylinder is bypassing internally or the system has a leak.
ABS Brake System Bleed
To open the ABS control valves you will need a scanner capable of doing
so, we have a link in the description of the video for the one we use. Plug
the scanner into the ALDL port.
The scanner will light up letting you know it is ready to be used.
Follow the prompts to navigate to the ABS bleed instructions which will show
you which wheel to bleed first and the procedure for doing so and the
remainder of the wheels as well.
Watch the ABS bleed video to see how to do the job correctly.
Some brake fluids are not compatible
with each other. Distinctive ratings define the chemicals in which the fluids are produced such as mineral oil, ester glycol and synthetic oils. Always add fluid from a sealed container to avoid dirt and moisture contamination.