Automotive braking systems use friction between moving and stationary surfaces to convert the kinetic energy of a moving vehicle into heat energy, allowing the vehicle to be stopped. Common braking systems include disc brakes and drum brakes. Disc brakes use pads that press against a rotating disc or rotor, while drum brakes use shoes that are pressed against the inner surface of a wheel cylinder. The braking force is created hydraulically using a brake pedal, master cylinder, lines and either calipers or wheel cylinders to apply force to the brakes. ABS systems modulate brake pressure to prevent wheel lock up during hard braking.

1. 1
AUTOMOTIVE BRAKING
SYSTEMS

2. 2
How it Works
Friction develops heat which
absorbs kinetic energy of the
car

3. 3
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.

4. 4
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

5. 5
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.

6. 6
BASIC PARTS
 Pedal assembly
 Hydraulic system
 Power booster
 Disc brake assembly
 Drum brake
assembly
 Parking brake

7. 7
DISC BRAKES
 Disc brakes use a
rotating disc with
two stationary
friction pads that are
pressed against to
rotor by the caliper
to create friction and
heat.
 Disc brakes are
more effective at
dissipating heat.

8. 8
Disc Brake Rotor
Rotor
Pads
Caliper
Piston
Brake
Line
Bleeder
screw
Through
Bolts

9. 9
Rotors

10. 10
Performance Rotors

11. 11
Caliper
 Boot
 Piston
 Seal
 Caliper
Housing
 Bleed Screw
 O-Ring
 Bushing
 Bolts

12. 12
Caliper*

13. 13
Disc Brake Pads
 Asbestos
 Metallic
 Semi-Metallic
 Organic

14. 14
Wheel Assembly

15. 15
Disc Brake Assembly

16. 16
Drum Brakes

17. 17
Drum Brakes

18. 18
Drum Brake Action
Adjust by driving in reverse and braking

19. 19
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

20. 20
Two Types of Drum Brakes

21. 21
Two Types of Drum Brakes

22. 22
HYDRAULIC SYSTEM
 Brake pedal assembly
 Power booster
 Master cylinder
 Proportioning valve
 Metering valve
 Warning light valve
 Lines
 Calipers
 Wheel cylinders

23. 23
Brake Light
 Hydraulic system
fails
 Parking brake is on

24. 24
Master Cylinder
 The master cylinder displaces brake fluid under
pressure to brake system.
 When brake pedal is depressed, push rod moves the
primary piston forward in the cylinder.
 Hydraulic pressure created and the force of the
primary piston spring moves the secondary piston
forward.
 forward movement of the pistons causes primary
cups to cover bypass holes, hydraulic pressure
builds up and is transmitted to the wheel cylinders.

25. 25
MASTER CYLINDER
 pedal retracts, the pistons allow fluid from
the reservoir to fill the chamber
 Special sensors within the master cylinder
used to monitor level of fluid in reservoir,
and alerts driver if pressure imbalance
develops.
 standard dual master cylinder gives front
and rear brakes separate hydraulic systems.

26. 26
Master Cylinder
 If a brake fluid leak occurs in one system,
the other system will still operate, making it
possible to. . .
 STOP THE CAR

27. 27
Master Cylinder
To
Front
Brakes
To Rear
Brakes
Master
Cylinder
Reservoirs
Power
Booster
Vacuum Line
Brake Pedal

28. 28
Reservoirs

29. 29
Reservoir Problems

30. 30
Power Brake Booster
Gain power from vacuum in intake manifold

31. 31
Booster
Operation

32. 32
Brake Lines
 Brake lines are stee
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

33. 33
Brake Lines
 Throughout the brake
system and into the wheel
(or brake) cylinders.
 The pressure placed
upon this fluid causes the
cylinder pistons to
 move, forcing the brake
shoes or friction pads and
brake drums or
 rotors to slow the
vehicle.

34. 34
Brake Parts

35. 35
Hydraulic Valves

36. 36
Hydraulic Action in the Caliper
 Squeeze Rotor
 Push out on Drum

37. 37
Basics of Hydraulics

38. 38
Hydraulic Action in the Wheel
Cylinder

39. 39
Braking Videos
http://www.raybestos.com/main.htm?techcenter.htm

40. 40
PARKING BRAKE
 Parking brake pedal or
lever
 Cables
 Adjuster
 Drum brake linkage
 Disc brake lever

41. 41
BRAKE INSPECTION
 Remove all four wheels of the vehicle.
 On drum brakes remove the drums and
wash brake dust with proper cleaner.
 Check brake pads and brakes shoes for
wear.
 Check drums and rotors for wear and
damage.

42. 42
Brake Fluid
 Litmus test
 Color
 Non compressible
 Resists boiling
 High &low
temperature stability
 Non-corrosive to
rubber parts
 Hydroscopic
– Absorbs water

43. 43
Brake Fluid
 DOT 3
 DOT4
 DOT5
– Silicone

44. 44
Brake Service
 Visual Inspection
 Measure
 Resurface
 Repair
 Recondition
 Bleed
 Test

45. 45
Problems

46. 46
ABS
 Modulator
 VSS/
 Vehicle
speed
sensors
 Electronic
Brake
Control Unit

47. 47
ABS
 Wheel locks up-
reduces power to that
wheel
 Pulsates brakes if
sliding
 Pulsates brakes on hard
braking
 Stops vehicle under
control
 NOT faster