CPP GENERAL PURPOSE BRAKE BLEEDING GUIDE
© 2003 Classic Performance Products, Inc.
No copies or reproductions in all or in part of this document may be made
without written consent of CPP
except in the express use for installing or troubleshooting CPP supplied
All Rights Reserved.
Read these instructions carefully and completely
before installing your kit! This guide is set up
to be generally followed in order. Here are a few basic to help ensure a
safe brake system:
- Following the steps in this guide will ensure that you
will easily pinpoint any trouble spots in your brake system while installing
and assembling the system, eliminating many headaches. "Follow it
to the T," and we are certain you will have a pleasurable experience
with your upgrade.
- Use only new brake fluid. Contaminated fluid can
cause damage to the sensitive hydraulic brake components during the bleeding
process, corrodes components and increases likelihood of system failure.
Even unused fluid that was opened at an earlier time should not be used.
Brake fluid is hygroscopic meaning that it absorbs moisture from the air.
This moisture degrades the properties of the brake fluid.
- Cleanliness is very important. Make sure you clean the
fittings and surrounding area before opening any part of the brake system
to keep contaminants from entering the fluid.
- Power brake upgrades, be sure to check for a minimum
of 18 in. of vacuum prior to performing the upgrade. Vehicles with
tall heads or superchargers most likely will not have sufficient vacuum.
If you do not have sufficient vacuum, check your intake manifold for clogging,
vacuum fittings and for collapsed vacuum lines. Also ask us about our 12
volt vacuum pump.
- Never eliminate loops from vacuum lines as these act
as moisture and vapor traps. Check the vacuum lines for gas odor or the
presence of moisture. Gas fumes can deteriorate the internal rubber components
of the booster.
- Do not use petroleum-based solvents to clean brake components.
Use only cleaning fluids specifically designed for brakes since they leave
no residue when they dry.
- Do not use compressed air to dry brake components, even
filtered air may contain moisture or traces of oil.
- Check brake lines for cracked, leaking or swollen lines,
these must be replaced.
- Do not move or drive the vehicle until a firm pedal is
Rear Disc Brakes and Parking Brake Adjustment
This is a critical item that many people miss when upgrading
to rear disc brakes. Our rear disc brake calipers that are equipped with
an parking brake are self-adjusting. Every time you use the parking brake
they adjusts themselves for pad wear by clicking to the next stop on the
internal ratchet. If you do not use your parking brake during normal operation
of the vehicle, over time the pads will wear and there will be insufficient
contact between the pads and the parking brake mechanisms. When this happens
the parking brake will never engage. This step should always be performed
prior to bleeding.
To adjust the parking brake while installing or servicing
the calipers, use the following directions. Failure to adjust the parking
brake can result in no parking brake, brakes dragging, overheating and
premature brake wear.
- If you are adjusting the parking brake after the system
has been bled, remove the master cylinder lid and make sure that the fluid
level is no more than 1/2 full, this is so that in the following steps
when the caliper piston is pressed back, fluid does not overflow the master.
- Remove the parking brake spring and lever arm. Remove
the seal and nylon washer from the adjusting screw and place them in a
- Turn the adjusting screw counterclockwise to tighten
it and collapse the pads until the pads are tight against the rotor.
- Note that the adjusting screw clamps the pads closed
when tightened counterclockwise. When the adjusting screw is turned counterclockwise
past a certain point, it turns the internal ratchet. This is how it is
adjusted. Adjusting the screw can be tricky because when the it is tightened
all the way, its hex head recedes into the caliper body and you can't get
a wrench around it.
- Turn the adjusting screw in counterclockwise by hand
until there is resistance.
- To push the adjusting screw back out to provide access
to it's hex, use two channel-locks to squeeze the rear brake pad and compress
the caliper piston. Place the wrenches on either side of the pad locating
the jaws on the pad bracketry and the body of the caliper.
- Then use a wrench to turn the adjusting screw counterclockwise
to change the position of its hex and slip the internal ratchet.
- Back the adjusting screw out by turning it clockwise,
place the lever arm over the adjusting screw hex and apply a medium amount
of hand force clockwise to the lever arm to push it past the lever stop
on the caliper. Once the force has been applied, the lever should be located
within 1/4" of the lever stop and should be easy to put on the adjusting
screw head. There should also be mild contact between the pads and the
rotor when properly adjusted. It is highly likely that this will need
to be done a number of times before it is properly adjusted.
- Remove the lever arm and replace the nylon bushing and
seal, then replace the lever arm and secure with the nut.
- Replace the return spring.
Bench Bleed and Test the Master Cylinder
Many people skip this VITALLY important step in bleeding
their brake system. Bench bleeding the master cylinder MUST be performed
any time a master cylinder is installed. If the master cylinder is not
bled, it will take you at least twice as long to bleed the system and then
there is no guarantee that you have removed all the air from the system.
The master cylinder test is a preliminary precaution and may need to be
performed at a later time should further troubleshooting need to take place.
DO NOT SKIP THIS STEP! Failure to follow these procedures is unsafe and
may void your warranty!
- All new master cylinders from Classic Performance include
a bench bleeding kit that includes everything you need to perform the bench
- Before bench bleeding the master, completely install
all of your brake components and upgrades including the master cylinder
and brake lines. This is so that you can hook up the master cylinder as
soon as possible after it has been bench bled to keep gravity from leeching
fluid from the master cylinder during the installation of the other components.
- After installing the system, remove the master cylinder
completely from the vehicle. Master cylinders MUST be bench bled outside
the vehicle and without any other components attached. This means that
if the kit is shipped with a booster, proportioning valve and plumb lines
attached to the master cylinder, they must all be removed prior to bench
- Be sure to place the master cylinder level in
a vice to secure it properly. If the master cylinder is not level, not
all the air will be able to be removed from the master cylinder. This is
one of the main reasons we bench bleed the master cylinder off of the vehicle,
to get it perfectly level during the bleeding process. (See fig. below)
Remove the master cylinder top and fill with brand new brake fluid
to the appropriate level as indicated in the master cylinder. This is generally
about 1/2" - 1" from the top of the reservoir lip to allow for
thermal expansion of the brake fluid.
- Insert the plastic fittings that fit into the two side
ports of the master cylinder, (Note: on dual ported master cylinders where
there are four ports, choose one side and use both ports on that one side
to perform the bleed process.) Insert one rubber tube into each of the
plastic fittings and the loose ends should be inserted into the master
cylinder reservoir. The plastic tab should be used to hold the tubes in
place by slipping it over the reservoir separator and the hoses through
the round holes.
- Cover the top of the master cylinder with a rag to help
prevent fluid from splattering in order to protect your person as well
as your vehicle. Be aware that brake fluid is mildly corrosive and may
damage painted surfaces.
- Using a wooden dowel or a blunt metal rod, compress
the master cylinder plunger with slow deep strokes.
- Once the large bubbles have subsided it should become
increasingly more difficult to compress the master cylinder piston. Continue
to do so with slow short strokes at the bottom of the piston stroke until
no more bubbles appear.
- The rubber hoses and plastic fittings may be removed
from the master cylinder.
- Secure the master cylinder top
- Now test the master cylinder by "blocking off"
the master cylinder ports using the correct size inverted flare plugs or
bolts with the appropriate thread size for the ports on your master cylinder.
Dual port master cylinders that have ports on both sides need to have all
four ports plugged. The protruding cone of the inverted flare seat in the
master cylinder port is made of a soft material that can easily be deformed
if over tightened. If using bolts, be sure to just snug the bolts so as
not to damage the cone seal surface. This cone mates with the inverted
flare (expanded mouth opening) of the brake lines. If you have the ability,
you can also drill a point into the end of the bolt to help prevent this
- Attempt to compress the master cylinder piston for approximately
30 seconds. The master should give a solid and unchanging resistance to
the constant force.
- Install the Master Cylinder and leave enough room on
the mounting nuts to allow for some movement of the master. This will allow
you some breathing room while screwing in the hydraulic lines to help prevent
cross-threading the fittings.
Bleeding the Lines
Many of you will be tempted to glaze over this section
thinking that you already know this. Continue reading anyway, just bear
with us. You may prevent small oversights that will cause major headaches.
We have devised this to assist you in the installation of your kit and
to reduce the number of technical calls in regards to these issues. Many
times we get calls from people who "should have known better."
So let's work together to make sure your installation will be as smooth
- For master cylinder upgrades to existing power booster
set ups, remove any residual vacuum in the booster by applying the brake
pedal a few times with the engine off.
- Remove the master cylinder cover and check the fluid
level. Make sure it is at the appropriate level for your master cylinder,
this is typically 1/2" to 1" from the lip. Be sure to check the
fluid level often during the bleeding process and add fluid as necessary
to prevent air from entering the master cylinder. If this happens you MUST
start over at bench bleeding the master!
- Replace the master cylinder cap
- The use of our Speed Bleeders will allow you to perform
this job by yourself by simply cracking the Speed Bleeder enough to allow
fluid to be forced through. The Speed Bleeder has an internal check valve
that prevents fluid and air from returning into the caliper once the pedal
is released. This removes the necessity of closing the bleeder screw before
the pedal is released, allowing one person to bleed the brakes. Otherwise
you will need an assistant to pump the brake pedal while you open and close
the bleeder screws at the appropriate times during this process.
- The wheel farthest away from the master cylinder is bled
first which in most cases is in this order: Right Rear, Left Rear, Right
Front, Left Front. Failure to bleed in the proper order will cause air
to remain in the lines. This is because if you bleed a short line, (ex.
front lines) before bleeding a long line (ex. rear lines), the fluid in
the short line will compress and prevent enough pressure from being built
up in the long line to expel the air. Furthermore, incorrect bleeding order
will cause pressure to build up on one side of the proportioning valve,
causing it to close on the low pressure side making it impossible to force
fluid to the rear lines. If this happens you will never be able to bleed
the system until you readjust the proportioning valve as described later
under the heading Test Combination/Proportioning Valve and then start over.
- It may be necessary to remove the Calipers from the caliper
brackets while leaving the hoses attached. The calipers must be oriented
in such a way as to ensure the bleeder screws point up. (See fig. below)
If you bleed the lines with the calipers on the rotor, air may become trapped
inside the caliper reservoir and the bleeding will be unsuccessful. The
caliper should be oriented in such a way as to allow air inside the caliper
internal reservoir to escape. Sometimes this means the bleeder screw is
pointing straight up and sometimes it is at a little bit of an angle. It
is recommended that you do not allow the caliper to hang from the brake
hose. Instead use a piece of wire or hangar to position the calipers correctly.
Otherwise damage to the brake hoses may result. If you do find it necessary
to remove the caliper from the rotor, be certain to insert a block that
is approximately the same thickness as the rotor between the brake pads
to prevent the caliper pistons from being pushed out of the caliper.
- Crack the bleeder screws at the appropriate wheel just
enough to make it easy to loosen later. Attach a length of 3/16" clear
plastic, vinyl tube to the end of the bleeder screw. Submerge the other
end of the tube into a container filled with brake fluid.
- Crack the bleeder screw open just enough to allow fluid
to leave the valve and have the assistant slowly and firmly apply pressure
to the pedal. Have the assistant hold the pressure on the pedal until you
see no more air bubbles coming out of the hose. Close the bleeder screw.
Then have the assistant release the brake pedal.
- Repeat step 8 until no more air is seen leaving the tube.
- Close the bleeder screw to the appropriate torque for
your application and proceed to the next wheel in the bleeding order, repeating
steps 8 and 9 for each. Be sure to check the fluid level in the master
- Refill the master cylinder to the appropriate level when
finished with the entire bleeding process.
- Check the pedal, it should feel solid when depressed
with no sponginess and should hold under constant pressure without dropping.
If necessary, repeat the entire process.
- If you are in doubt of the effectiveness of the brake
system DO NOT DRIVE THE VEHICLE!
Why change to Disc Brakes?
- Disc brakes offer a significant advantage over drum brakes
in a number of areas, the most important is in safety.
- Disc brakes resist heat induced brake fade. The design
of disc brakes dissipates heat much more quickly than drum brakes. Also,
heat causes the disc to expand which has no effect on braking ability where
as the drum expands it increases the amount of travel required for the
shoes to apply effective stopping force.
- Disc brakes resist water induced brake fade. When disc
brakes become wet, the large majority of the water is spun off of the disc
during rotation. The residual water evaporates from the heat caused during
braking. In a drum brake set up, water can become trapped inside the drum
and act as a lubricant between the drum and shoes causing water induced
- Disc brakes are better at straight-line stops. Drum brakes
have a tendency to pull due to inconsistent alignment of the shoes from
the left to right wheels due to a dependency on multiple complex floating
mechanisms. These inconsistencies can cause the car to veer unexpectedly
to one side or the other during panic braking. Since disc brakes apply
equal force through clamping, they are much safer during straight line
- Ease of serviceability. Disc brakes are much easier to
service than drum brakes.
- Lighter weight
- Drawback is that disc brakes require the addition of
a power brake booster