1.
Brake System Operation: Back
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Vehicle
brake system operation begins with the driver and
the application of the brake pedal. Brakes slow and
stop a vehicle by transforming vehicle motion into
heat energy. The amount of heat produced is proportional
to the vehicle speed and driver foot pressure on the
brake pedal. Fast vehicle speeds and quick stops produce
more heat. The brake system is comprised of many sub-systems.
Stopping a vehicle requires that all brake sub-systems
work together. The first system that is activated
during a stop is the Apply system.
2.
Apply system: Back
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The
driver depresses the brake pedal, operating the brake
pedal linkage. The linkage connects the pedal to the
Power Brake Booster or Master Cylinder. Located near
the brake pedal is the stop lamp switch. Proper adjustment
of this switch is necessary to illuminate the brake
lights.
3.
Power Brake Booster: Back
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Most
vehicles are equipped with a Power Brake Booster.
The Booster increases brake pedal force (Boost System).
The booster links the brake pedal Apply system to
the Master Cylinder Assembly.
4.
Master Cylinder Assembly: Back
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Today's
high performance hydraulic brake master cylinders
are the result of years of component and design improvements.
Applying brake pedal force moves pistons in the master
cylinder, forcing pressurized brake fluid out through
steel brake lines and rubber flexible brake hoses.
Master Cylinders are single-bore-dual hydraulic channels
that allow one channel to operate should the other
channel fail. Brake fluid from the Master Cylinder
flows through steel brake lines and flexible reinforced
rubber hoses. Raybestos® brand brakes features
Master Cylinders that are manufactured to exact original
equipment specifications. The benefit is customer
satisfaction and confidence. Strict adherence to tolerances,
specifications and highest quality internal components,
ensures durability and dependability.
5.
Brake Fluid: Back
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Extremely
important and often overlooked, brake fluid is the
medium that transmits energy from pressure on the
brake pedal to the caliper and wheel cylinder pistons.
All brake fluids eventually wear out. Raybestos®
brand brake fluid is manufactured with corrosion inhibitors
to help protect the brake system. Corrosion can pit
the bores of the master cylinder, calipers, wheel
cylinders, and ABS components. Some manufactures recommend
flushing the brake system every 2 years or 24 thousand
miles. Consult your owner's manual for your vehicle's
brake fluid type and service recommendation. Brake
fluid absorbs moisture and can damage paint. Use caution
when handling brake fluid.
6.
Hoses & Steel Lines: Back
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Brake
hoses and steel lines transmit brake fluid pressure
produced in the master cylinder. From the steel lines,
brake fluid pressure is channeled through Balance
Control Systems. All features included in original
equipment brake hoses such as brackets, grommets,
molded plastic guards, or wire clips are found on
Raybestos brake hoses. Double wall steel brake lines
are coated to resist rust and corrosion. All hoses
and steel lines meet or exceed Department of Transportation
(DOT), Society of Automotive Engineers (SAE), and
Federal Motor Vehicle Safety Standard (FMVSS) specifications.
The resulting benefits are optimal protection, service
life and safety.
7.
Balance Control / Warning system: Back
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Balance
control systems typically consist of a combination
valve located on or near the master cylinder or in
the steel lines between calipers and wheel cylinders.
The balance control system ensures that brakes apply
quickly, simultaneously, and at a balanced pressure
for safest operation. An instrument panel lamp (red
brake warning light) signals the driver of a hydraulic
system failure, parking brake application, or when
low brake fluid levels occur. On many newer vehicles,
worn out friction material will also illuminate the
red brake warning light.
8.
Caliper Assembly: Back
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The
brake calipers are large hydraulic clamps. Calipers
have one or more pistons that move outward with increased
brake fluid pressure, forcing the friction material
(brake pads) to contact the rotor surface. When the
driver releases foot pressure from the brake pedal,
the caliper piston seal retracts, pulling the brake
pads off of the rotor surface. Caliper pistons are
self-adjusting, the caliper piston seal maintains
proper pad-to-rotor contact as the pads wear. Raybestos
re-manufactures calipers. All are leak-tested, coated
with rust inhibiting formula, and feature quality
o-rings, seals and boots. Caliper integrity is vital
to the function of the brake system. Seals, o-rings,
slides, and lubrication become compromised as a result
of exposure to road grit, corrosion, deposits, heat
and contaminated brake fluid. Wheel cylinders are
used with drum brake systems. Brake fluid piped to
wheel cylinders provides hydraulic pressure to the
movable pistons within each cylinder. This pressure
forces the brake shoes into the drums. When the driver
releases foot pedal pressure, large return springs
(hardware) secured to the brake shoes, forces the
wheel cylinder pistons back to their resting position.
9.
Hardware: Back
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Hardware
consists of a variety of parts designed to assist
in restoring your brake system to "Like New Performance".
Caliper anti-rattle clips, seals, pins, and dust boots;
along with drum shoe return springs, hold down springs,
and adjuster assemblies, help to maintain consistent,
balanced braking. These Raybestos components exceed
quality standards providing the highest temperature
rating and service life.
10.
Brake Pads and Shoes: Back
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Friction
material includes disc brake pads and drum brake shoes.
At each wheel, pressurized brake fluid moves pistons.
Pistons press brake friction material against a rotating
rotor or drum, slowing the vehicle. Caliper pistons
move brake pads, while wheel cylinder pistons move
brake shoes. Raybestos premium disc brake pads and
drum brake shoes are 100% non-asbestos formulations.
Friction materials are designed to match original
equipment specifications and provide the quietest
and safest braking in the industry. Friction pads
and shoes are available in a variety of formulations
designed to meet the demands, needs, and driving conditions
customers require.
11. Rotor Assembly / Rear Drum
Brake Assembly: Back
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Late model brake systems on most cars and light trucks
utilize disc brake rotors on the front, and brake
shoe drums on the rear. Rotors and drums are both
very important to the effectiveness of vehicle braking.
Our technical skills and manufacturing facilities
enable us to produce nearly every brake drum and rotor
configuration on the road today. Raybestos® brand
VSM™ rotors and drums feature outstanding casting
quality, consistent brake surface thickness and finish,
and meet or exceed original equipment specifications.
The advantage is consistent, quiet, confident braking.
Drums and rotors must dissipate heat and stand up
to continuous contact with water, road grit, and abrasives.
Strict adherence to torque specifications of wheel
lug nuts is vital to maintaining the tolerances we
adhere to during manufacturing.
12.
Anti-Lock Braking System (ABS): Back
to top
ABS
systems are add-on devices to conventional base brake
systems. ABS allows the driver to maintain steering
control of the vehicle while in hard braking situations.
Computerized ABS is designed to keep the wheels from
locking as the brakes are applied. A locked wheel
provides very little or no directional control. Drivers
should maintain firm brake pressure on the brake pedal
of ABS equipped vehicles, because pumping the brakes
only extends the stopping distance. Drivers may experience
a pulsation in the brake pedal, or pedal kick back
during an ABS stop. This is normal and not to be confused
with a conventional brake pedal pulsation. Major components
of the anti-lock brake system consist of a computer
module, hydraulic assembly, speed sensor(s), wiring,
and the amber ABS brake warning light.
13. Computer Module: Back
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The
electronic brake control module monitors the ABS system
during start up and during vehicle operation. This
initial test is referred to as a "self test".
During the self-test the amber light may remain on
for 3 to 5 seconds. The light is turned off if the
system passes the self-test. Should the module detect
an error, it will illuminate the amber ABS warning
light and disable the antilock function. While you
are driving the vehicle, the module monitors wheel
speed data from each wheel speed sensor, and controls
the hydraulic assembly during an ABS stop.
14.
Hydraulic Assembly: Back
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The
hydraulic assembly is a series of electro-hydraulic
valves that regulate individual brake line pressure
at the wheels or axle. Modulation can occur as many
as 15 times per second. This action helps prevent
wheel lock up and maintains vehicle control.
15.
Wheel Speed Sensor: Back
to top
Wheel
speed sensors are located individually at each wheel
or axle. These sensors generate a signal that changes
with wheel speed. Imagine one wheel on dry pavement
and one wheel on ice. A speed sensor signal that suddenly
drops off indicates that one or more wheels are approaching
lock up. This information is being monitored by the
computer, which in turn commands the hydraulic modulator
to regulate line pressure at the affected wheels.
When accessible during normal brake service, wheel
speed sensors should be cleaned and air gap checked.
