Athena Mz 6th Period

1. Automotive brakes- provide a means of using friction to either slow, stop, or

hold the wheels of a vehicle
2. Inertia- when a car is moving down the highway it has a tremendous amount
of stored energy in the form of inertia
3. Hydraulic brakes- a conventional hydraulic brake system is combined with
an electric regenerative braking system
4. Brake pedal assembly- is a foot lever for operating master cylinder and
power booster
5. Master cylinder- a hydraulic-piston pump that develops pressure for the
hydraulic brake system
6. Brake booster- is a vacuum, electric, or power steering operated device that
assists brake pedal application
7. Brake lines and Hoses- are metal tubing and rubber hose that transmit
pressure to the wheel brake assemblies
8. Wheel brake assemblies- are hydraulic-mechanical mechanisms that use
hydraulic pressure to produce friction to slow or stop each wheel
9. Emergency brakes- are mechanical or electric systems for applying rear
brake assemblies
10. Disc brake assembly- consists of a caliper, brake pads, a disc, and other
related hardware
11. Caliper- is an assembly that holds a hydraulic cylinder, piston, seals, and
brake pads
12. Caliper cylinder- is a machined hole in the caliper the piston fits into this
cylinder
13. Brake pads- are friction members that are pushed against the disc by the
action of the master cylinder, caliper cylinder, and piston
14. Brake disc- a large metal rotor that holds the wheel and tire and uses
friction from the brake pads to stop or slow wheel rotation
15. Drum brake assembly- consists of a backing plate, a wheel cylinder, brake
shoes and linings, retracting springs, hold-down springs, a brake drum, and
an automatic adjusting mechanism
16. Wheel cylinder assembly- houses a hydraulic piston that is forced outward
by fluid pressure
17. Brake shoes- friction units that are pushed against the rotating brake drum
by the action of the hydraulic wheel cylinder
18. Brake drum- rubs against the brake shoes to stop or slow wheel rotation
19. Braking ratio- refers to the comparison of front wheel braking effort to rear
wheel braking effort
20. hydraulic system- a system that uses a liquid to transmit motion or pressure
from one point to another
21. Cup and Piston- in the master cylinder are used to pressurize the brake
system. When they are pushed forward, they trap the fluid, building pressure
22. Intake port- allows fluid to enter the rear of the cylinder as the piston slides
forward
23. Compensating port- eleases extra pressure when the piston returns to the
released position
24. residual pressure valves- maintain residual fluid pressure of approximately
10 psi to help keep contaminants out of the system
25. Rubber boot- prevents dust, dirt, and moisture from entering the back of the
master cylinder
26. Master cylinder reservoir- stores an extra supply of brake fluid. The
reservoir may be cast as part of the housing, or it may be a removable plastic
part
27. Dual master cylinder- also called the tandem master cylinder, has two
hydraulic pistons and two fuel reservoirs
28. Primary piston- in the dual master cylinder, it is the term for the rear piston
assembly
29. Secondary piston- in a dual brake master cylinder system, it is the term for
the front piston
30.Power brakes- uses a booster and either engine vacuum, electric pump, or
hydraulic pressure to assist brake pedal application
31. Vacuum booster- uses engine vacuum (or vacuum created by a separate
pump on diesel engines) to apply the hydraulic brake system
32. Atmospheric suspended brake booster- has atmospheric pressure (normal
air pressure) on both sides of the diaphragm or piston when the brake pedal
is released
33. Vacuum suspended brake booster- has vacuum on both sides of the piston
or diaphragm when the brake pedal is released
34. Hydraulic booster- uses power steering pump pressure to help the driver
apply the brake pedal, sometimes called the hydro-boost or hydra-boost
35. Brake fluid- is a specially blended hydraulic fluid that transfers pressure to
the wheel brake assemblies
36. Brake lines and Brake hoses- transfer fluid pres- sure from the master
cylinder to the wheel brake assemblies
37. Longitudinally split- front to rear brake system, one master cylinder piston
operates the front wheel brake assemblies and the other operates the rear
brake assemblies
38. Diagonally split- corner to corner brake system has each master cylinder
piston operating the brake assemblies on opposite corners of the vehicle
39. Brake caliper- includes the caliper housing, piston, piston seal, dust boot,
brake pads, special hardware, and a bleeder screw
40.Piston seal- in the caliper prevents pressure leakage between the piston and
the cylinder
41. Piston boot- keeps road dirt and water off the caliper piston and the wall of
the cylinder
42. Bleeder screw- allows air to be removed from the hydraulic brake system
43. Disc brake pads- are steel plates to which linings are riveted or bonded
44. Brake pad linings- normally made of heat resistant organic or semi metallic,
metal-particle filled, friction material
45. Anti-rattle clips- are frequently used to keep the brake pads from vibrating
and rattling
46. Pad-wear sensor- a metal tab on the brake pad that informs driver of worn
brake pad linings
47. Brake rotor- uses friction from the brake pads to slow or stop wheel rotation
48. Floating caliper- is mounted on two bolts supported by rubber bushings
49. Sliding caliper- is a one-piston caliper that is mounted in slots machined in
the caliper adapter
50.Fixed caliper- normally uses more than one piston and caliper cylinder. The
caliper is bolted directly to the steering knuckle
51. Runout- tolerated vehicle part specific measurements for part movement or
wobble
52. Brake backing plate- holds the shoes, springs, wheel cylinder, and other
parts inside the brake drum. It also helps keep road dirt and water off the
brakes
53. Wheel cylinder- consists of a cylinder or hous- ing, an expander spring,
rubber cups, pistons, dust boots, and a bleeder screw
54. Wheel cylinder housing- forms the enclosure for the other parts of the
assembly. It has a precision honed cylinder in it for the pistons, the cups, and
the spring
55. Wheel cylinder boots- keep road dirt and water out of the cylinder. They
snap into grooves on the outside of the housing
56. Wheel cylinder pistons- are metal or plastic plungers that transfer force out
of the wheel cylinder assembly
57. Wheel cylinder cups- are rubber seals that keep fluid from leaking past the
pistons
58. Wheel cylinder spring- helps hold the rubber cups against the pistons when
the wheel cylinder assembly is not pressurized
59. Cup expanders- help press the outer edges of the cups against the wall of
the wheel cylinder
60.Drum brake shoe assemblies- rub against the revolving brake drum to pro-
duce braking action
61. Primary brake shoe- is the front shoe. It nor- mally has a slightly shorter
lining than the secondary shoe
62. Secondary brake shoe- is the rear shoe. It has the largest lining surface area
63. Retracting springs- pull the brake shoes away from the brake drums when
the brake pedal is released
64. Hold down springs- hold the brake shoes against the backing plate when the
brakes are in the released position
65. Brake shoe adjusters- maintain the correct drum- to-lining clearance as the
brake linings wear
66. Star wheel- screw-type brake shoe adjusting mechanism
67. Self-energizing action- when the brake shoes are forced against the rotating
drum, they are pulled away from their pivot point by friction
68. Servo action- with most drum brake designs, shoe energization is
supplemented by servo action. Servo action results when the front shoe
helps apply the rear shoe
69. Spotlight switch- is a spring-loaded electrical switch that operates the rear
brake lights of the vehicle
70. Brake warning light switch- also called the pressure differential valve,
warns the driver of loss of pressure on one side of the dual brake system
 71. Low fluid warning light switch- turns on a dash light if the brake fluid in the
master cylinder becomes low
72. Metering wheel- is designed to equalize braking action at each wheel during
light brake applications
73. Proportioning valve- is also used to equalize braking action in systems with
front disc brakes and rear drum brakes
74. combination valve- is a single unit that functions as a brake warning light
switch, a metering valve, and or a proportioning valve
75. Electric parking brake- uses the brake system control module to operate an
electric servo motor that mechanically engages the rear brakes

The ones that are highlighted are not given a clear definition but are included with
the said term