2. Stop the vehicle by converting kinetic energy to heat
energy.
Heat energy is created in the brakes by friction.
Friction is created between a moving and non-
moving surface at each wheel to generate the heat.
Discs and drum brakes are the most common type of
braking system used.
3. Pedal arm
Push rod
Master cylinder
Brake linings
proportioning valves
Pressure valves
Metering valves
T joint
flexible lining
Calipers
5. BRAKING FUNDAMENTALS
PRINCIPLE:
Friction between braking surfaces converts kinetic energy into heat.
In drum brakes, wheel cylinders force brake linings against the inside of the drum.
In disc brakes, pads are forced against a brake disc.
Several factors can influence Vehicle Braking:
Road surface
Road conditions
Weight of the vehicle
Load on the wheels during stopping
How the vehicle is being driven.
A basic Braking system has a:
Brake pedal
Master cylinder to provide hydraulic pressure
Brake linings and hoses to connect the master cylinder to the brake assemblies
Brake assemblies – Drum or Disc that stop the wheels.
6. DRUM & DISC BRAKES:
Drum brakes have a brake shoe that expands against the inside of a drum.
Disc brakes clamp a flat disc between two pads.
COEFFICIENT OF FRICTION:
The coefficient of friction is the measurement of friction between pairs of
surfaces.
STOPPING DISTANCE:
The distance in which the vehicle stops by applying force.
BRAKE FADE:
It is the reduction in stopping power caused by a build up of heat in the braking surfaces.
WEIGHT TRANSFER:
In dynamic braking condition weight transfers from rear wheels to
front wheels
SKIDDING:
When force of braking exceeds force of adhesion between tires and road
7. Drum brakes have a drum
attached to the wheel hub and
braking occurs by means of
brake shoes, expanding
against the inside of the drum.
A drum brake is a brake in
which the friction is caused by
a set of shoes or pads that
press against the inner surface
of a rotating drum. The drum
is connected to a rotating
wheel.
8. With disc brakes, a disc attached to
the wheel hub may be clamped
between 2 brake pads.
On light vehicles, both of these
systems are hydraulically operated.
The brake pedal operates a master
cylinder. Hydraulic lines and hoses
connect the master cylinder to
brake cylinders at the wheels.
Most modern light vehicles have
either disc brakes on the front
wheels and drum brakes on the
rear, or disc brakes on all 4 wheels.
Disc brakes require greater forces
to operate them. A brake booster
assists the driver by increasing the
force applied to the master cylinder
when the brake is operated.
9. DISC BRAKE DRUM BRAKE
Better ventilation property
than drum brake.
Low ventilation property.
Uniform wear of frictional
force between pads and
disc.
Non uniform wear of
frictional force.
Design of disc brake is
easy.
It has complex design.
Disc brake have low weight. 20% more weight than
disc.
It has better anti - fade
characteristics.
It has poor anti – fade
characteristics.
Replacing of frictional pads
is easily.
Replacing of frictional pads
is difficult.
Total frictional area of pads Total frictional area of pads
10. ABS is a system on motor vehicles which prevents the wheels
from locking while braking.
The purpose of ABS is:
To allow the driver to maintain steering control
To shorten braking distances
A typical ABS is composed of:
A central electric unit
Four wheel speed sensors (one for each wheel)
Two or more hydraulic valves on the brake circuit
The electronic unit constantly monitors the rotation speed of
each wheel. When it senses that one or more wheels is rotating
slower than the others, it moves the valves to decrease the
pressure on the braking circuit, effectively reducing the braking
force on that wheel.
11. ADVANTAGE OF ABS
It can be used for reducing the stopping distance.
It enables to steer when brakes are firmly applied.
It allows braking firmly on surface with different level of grips.
It can review and adjust the deriver’s driving.
DISADVANTAGE OF ABS
Driver may takes more risks when driving with vehicles fitted with ABS.
people who are inexperienced in using ABS may respond inappropriately when
they activate the system.
12. HYDRAULIC BRAKES
The principle of hydraulic brakes based on the Pascal’s law.
The function of all the components of hydraulic brakes:
Master cylinder:
Distribution of fluid in the pipe lines.
Calipers:
Calipers are used to stop the vehicle by applying
clamping force with brake pads to rotating disc. FLEXIBLE LINING
ROTOR with CALIPER BENZO BOLT DRUM
BRAKE
13. DOTs 3
DOTs 4 DOTs 5
Less viscous as compare
to other.
It has moderate viscosity. Highly viscous as compare
to other.
Air bubble formation is
high.
Air bubble formation is
less.
No chances of air bubble
formation in pipelines.
Boiling point is 401 degree
Fahrenheit.
Boiling point is 446 degree
Fahrenheit.
Boiling point is 500 degree
Fahrenheit.
FLUIDS
There are three types of fluid using in hydraulic brake system.
15. The primary components of the park brake system are:
Parking brake cables
Disc brake caliper fitted with park brake
Park brake lever on drum brakes.
The mechanical park brake is normally hand operated by a brake
handle located on the wheels floor or under the dash. In either
position, it is in easy reach for the driver to apply.
On vehicles fitted with 4 wheel disc brakes, the park brake is
applied at the rear caliper by the cable-operated system.
16. LAYOUTS OF BRAKES ASSEMBLY
Brakes are bedded in two types mainly.
Diagonally split Rear – Rear and Front - Front
ADVANTAGE OF DAIGONALY SPLIT OVER THE OTHER
BRAKES LAYOUT:
It helps to safe the one circuit of vehicle using tandem master cylinder
if one lining is failed.
17. The single-piston master cylinder
transforms the applied pedal force
into an hydraulic pressure which is
transmitted simultaneously to all
four wheels.
The master cylinder is connected to
the brake pedal via a pushrod.
The rod from the brake pedal
pushes on the piston. It moves,
closing off the compensating port
and trapping fluid ahead of the
primary cup. Any fluid trapped in the
cylinder is then forced through a
valve called a residual pressure
valve, into the brake lines.
18. The tandem master cylinder
transforms applied brake force into
hydraulic pressure which is
transferred to the wheel units
through two separate circuits. This
provides residual braking in the
event of fluid loss.
When the brake is applied, the
primary piston moves and closes
its compensating port. Fluid
pressure rises, and acts on the
secondary piston. It moves, closes
its compensating port. Pressure
builds up in this circuit. Both
pistons then move and displace
fluid into their separate circuits and
apply the brakes.
20. BLEEDING
It means removal of air bubble
present in the pipelines. The air
bubble block the transfer of
pressure from calliper to master
cylinder.
Bleeding in four Bleeding in two
wheeler wheeler
NEW TECHNOLOGY
According to new technology single
Man can do the bleeding using these
Materials.
Single person bleeding process