This document discusses automotive braking systems. It describes how braking systems work by converting kinetic energy to heat energy through friction between moving and non-moving surfaces at each wheel. The most common types of braking systems are disc and drum brakes. It then explains the basic components and functioning of drum brakes, disc brakes, and hydraulic braking systems. Key components discussed include the master cylinder, brake lines, calipers, wheel cylinders, rotors, and pads. Factors that can affect braking performance and types of brake linings are also outlined.

1. Braking Systems For Automobiles
Dr.S.John Alexis

2. 2
Basics of Hydraulics

3. 3
Hydraulic Action in the Wheel Cylinder

4. Advantage by Hydraulics

5. 5
PURPOSE OF BRAKING SYSTEM
• Stop the vehicle by converting the kinetic energy of
the vehicle to heat energy.
• Heat energy is created in the brakes by friction.
• Friction is created between a moving and a non-
moving surface at each wheel to generate the heat.
• Disc and drum brakes are the most common type of
braking systems used.

6. 6
Factors Effecting Braking*
• Number of wheels braking.
• Weight of vehicle.
• Type of friction material.
• Surface area of friction
material.
• Size or discs or drums
• Tire traction.
• Road surface.
• Load transfer.
• Incline or decline of
road. (gravity)
• Engine braking.
• Pressure applied

7. Disc and Drum Brakes
• Disc brakes are found on almost all vehicles now.
• Older cars and trucks had a combination of disc and
drum brakes.
• At one time vehicles came with drum brakes only
(1970 and older)

8. Types of Linings
• Asbestos- these have phased out, very hazardous to
breath the dust.
• Organic- mixture of asbestos and organic materials
with a resin binder
• Semi-metallic- organic mixed with metal shavings,
last longer and very good at dissipating heat.
• Ceramic – low dust output, provide exceptional
braking performance
• Carbon/Kevlar- Motor sports application, not used
on road vehicles because of cost and they take time
to warm up.
• This is why we don’t use a bow gun to clean brakes or brake parts
(asbestos is hazardous in the airborne form)

9. 9
Types of Braking Systems
• Service brakes. It’s the
primary braking
system using a the
pedal connected to a
hydraulic system
causing it to operate.
• Parking brakes. It’s
mechanically applied
by a lever or pedal.

10. Drum Brake System

11. Drum Parts
Hardware Backing plate
Drum
Wheel
Cylinder
Adjusting Screw

12. 12
Drum Brake Action
Adjust by driving in reverse and braking

13. 13
DRUM BRAKES
• Wheel Cylinder
 .Backing Plate
 .Secondary Brake
Shoe
 Upper Return
Spring
 Parking Brake
Lever
 Primary Brake
Shoe
 Piston
 Adjuster
 Anchor Pin
 .Lower Return
Spring

14. 14
HYDRAULIC SYSTEM
• Brake pedal assembly
• Power booster
• Master cylinder
• Proportioning valve
• Metering valve
• Warning light valve
• Lines
• Calipers
• Wheel cylinders

15. 15
Master Cylinder
To
Front Brakes
To Rear
Brakes
Master
Cylinder
Reservoirs
Power
Booster
Vacuum Line
Brake Pedal

16. 16
Disc Brake Rotor
Rotor
Pads
Caliper
Piston
Brake Line
Bleeder
screw
Through
Bolts

17. 17
Caliper
• Boot
• Piston
• Seal
• Caliper Housing
• Bleed Screw
• O-Ring
• Bushing
• Bolts

18. Sliding Caliper
• Applies pressure to
two pads on opposite
sides of rotor
• Caliper
– Sliding
– Fixed
• Friction Material
exposed to air

19. Fixed Caliper
• Applies two pistons to
opposite sides of rotor
• Caliper stays
stationary
• Disc Brakes require
higher hydraulic
pressure

20. Braking Dynamics
• Weight Transfer
• Weight Distribution
• Braking Power
• Friction Efficiency
– Brake to Wheel
– Wheel to Road Surface
• Traction Efficiency
– Skidding

21. 21
Brake Lines
• Brake lines are steel
tubing with copper
and lead coatings to
prevent rust and
corrosion.
• As the brake pedal is
depressed, it moves
pistons within the
master cylinder and
forcing hydraulic brake
fluid

22. 22
Brake Lines

23. 23
ABS
• Wheel locks up-
reduces power to that
wheel
• Pulsates brakes if
sliding
• Pulsates brakes on hard
braking
• Stops vehicle under
control
• NOT faster