Chapter 23 Terms

Drum brake assembly

A brake system that uses a wheel cylinder to force two brake shoes against a rotating drum.

Floating caliper

A caliper that moves when the disc brakes are applied.

Wheel cylinder

A device used to convert hydraulic fluid pressure from the master cylinder to mechanical force, pushing out two pistons to apply the brakes.

Control module

A higher-level module that directs lower-level modules

Asbestos

A long, thin, fibrous silicate mineral with insulating properties, which can cause cancer when inhaled.

Accumulator

A variable and pattern designed to keep a running total through multiple iterations

Pressure differential switch

Alerts if there is a leak in the brake line

Bleeder screw

Allows air to be removed from the hydraulic brake system.

Anti-Lock Braking System (ABS)

Allows the driver to stop without brake lockup. Standard equipment in many newer vehicles. Designed to be used by applying steady pressure on the brake pedal.

Dust boot

Cover the piston to keep dust and water away from inner seal, reducing the possibility of the piston sticking

Metering valve

Designed to equalize braking action at each wheel during light braking applications.

Brake shoe

Friction units that are pushed against the rotation brake drum by the action of the hydraulic wheel cylinder

wheel speed sensors

Magnetic sensor used in an anti-lock brake system to measure wheel speed

Primary Cup

Mounted on the front of each piston and used to develop hydraulic pressure

Brake hoses

Part of the brake lines that allows flexing in the hydraulic system.

Hydraulic pressure

The pressure in the liquid in a hydraulic arm

Secondary brake shoe

The rear shoe. Typically has the largest lining.

Rotor

The rotating member of an electrical machine.

Hydraulics

The use of a liquid flowing under pressure to transmit power from one location to another.

Foundation Brakes

Used at each wheel. Most common being the S-Cam drum Brake

Hydraulic modulator

_______________________ is common to all vehicles equipped with ABS.

Traction control system

a computer controlled system which will reduce engine torque and or apply a brake to reduce wheel spin under accceleration

hydraulic system

a system that multiplies force by transmitting pressure from a small surface area through a confined fluid to a larger surface area

Parking brakes

also called emergency brakes, provide a mechanical means of applying the brakes

Emergency brakes

also called parking brakes, provide a mechanical means of applying the brakes

master cylinder

creates the pressure used to apply the breaks

Disc brake caliper

device in a disc brake system that is mounted straddling the brake disc. The caliper contains at least one piston and is used to provide clamping force of the brake pads on the disc.

kinetic energy

energy of motion

Cup expanders

help press the outer edges of the cups against the wall of the wheel cylinders

Brake fade

loss of brake effectiveness due to overheating

Wheel cylinder pistons

metal or plastic plungers that transfer force out of the wheel cylinder assembly

Secondary Cup

mounted on the rear of each piston and used to prevent fluid leakage between the two chambers or from the rear of the master cylinder

Diagonal split brake system

one master cylinder piston operates one front brake and one rear brake on opposite sides

Power brakes

require less physical effort on the brake pedal

Servo action

results when the primary shoe helps apply the secondary shoe

pistons

sliding pieces within cylinders that move back and forth

Brake line

small diameter, rigid steel tube the connects the brake system to the brake hose which connects to the wheel cylinders

coefficient of friction

the ratio of the force of friction to the normal force acting between two objects

Pumping

the repeated application of the pedal in quick movements

low-fluid warning light switch

turns on a dash light if the brake fluid in the master cylinder becomes low.

Proportioning valve

used to equalize braking action in systems with front disc brakes and rear drum brakes

reservoir

1. (n.) reserves, large supply (Igor the Indomitable had quite a reservoir of strengh and could lift ten tons, even after running 700 miles, jumping over three mountains, and swimming across an ocean.) 2. (n.) a body of water used for storing water (After graduation, the more rebellious members of the senior class jumped into the town reservoir used for drinking water.)

Braking ratio

The amount of braking the front brakes do compared to the rear.

brake fluid

The fluid used in the hydraulic brake system.

Primary brake shoe

The front shoe, typically has a shorter lining.

Pascal's law

Pressure exerted by a confined fluid acts undiminished equally in all directions.

Quick take-up Master Cylinder

Provide a large volume of fluid on the first stroke of the brake pedal.

push rod

Pushes the slack adjuster

Combination valve

Single unit that functions as a brake warning light switch, a metering valve, and/or a proportioning valve

Brake drum

Surface area the brake shoes push against to slow the rear wheels.

Backing plate

Surface at the end of the brake assembly against which rotors and stators are pressed