Question 1

Pascal's Law applies to brake systems.

Accepted Answer

Pascal's Law states that a change in pressure at any point in an enclosed fluid is transmitted equally throughout the fluid. This principle is used in brake systems, where the force applied to the brake pedal creates a pressure increase in the brake fluid, which is transmitted to the brake pads or shoes to initiate braking action.

Question 2

Metering valves hold the rear brakes off until the front brakes have applied.

Accepted Answer

Metering valves are used to delay the application of the front brakes until the rear brakes have had a chance to engage, ensuring balanced braking and preventing the front brakes from doing all the work too quickly.

Question 3

Two technicians are discussing pressure controllers. Technician A says that RWAL systems have only one solenoid for each wheel or axle. Technician B says the isolation/dump valve for a RWAL system may be referred to as the RWAL accumulator. Who is correct?

Accepted Answer

Technician A is correct because RWAL (Rear Wheel Anti-Lock) systems typically have one solenoid per wheel or axle to control the braking pressure, ensuring that the wheels do not lock up during braking. Technician B is incorrect because the isolation/dump valve in an RWAL system is not referred to as the RWAL accumulator; the accumulator is a separate component that stores brake fluid under pressure.

Question 4

What statement is true about ABS systems?

Accepted Answer

ABS systems require speed sensors on the ABS-equipped axles to detect when a wheel is about to lock up during braking and to modulate the brakes to prevent lockup, which helps to shorten stopping distance. They do not require vacuum controllers or mechanical controllers.

Question 5

Two technicians are discussing brake fluid. Technician A says that different DOT fluid numbers can be mixed without affecting performance. Technician B says that silicone brake fluid can be used in any braking system and can be mixed with other DOT levels. Who is correct?

Accepted Answer

Both statements are incorrect. Different DOT fluid numbers should never be mixed as it can affect performance and safety. Silicone brake fluid is not compatible with most braking systems and should not be mixed with other types of brake fluid.

Question 6

Two technicians are discussing power boosters. Technician A says that vacuum is the only source of power for a booster. Technician B says that hydro-boost is powered by the vehicle's power steering pump. Who is correct?

Accepted Answer

Hydro-boost systems use pressurized fluid from the power steering pump to assist with brake application. Therefore, Technician B is correct. Technician A is incorrect because there are also hydraulic boosters that use hydraulic pressure from the power steering pump.

Question 7

Traction control is meant to assist on slick road surfaces and in mud-bogging.

Accepted Answer

The answer of Traction control is meant to assist on...

Question 8

Two technicians are discussing brake operation. Technician A says that return springs cause the brake components to engage when the brake pedal is pressed. Technician B says that return springs are on the brake pedal, the master cylinder, and at any drum brake shoes. Who is correct?

Accepted Answer

Technician B is correct. Return springs are located on the brake pedal, the master cylinder, and at any drum brake shoes. These springs help to retract the brake components when the brake pedal is released. Technician A is incorrect because return springs do not cause the brake components to engage when the pedal is pressed; rather, they help to release the components when the pedal is released.

Question 9

Proportioning valves control the amount of pressure that the front and rear brakes receive during braking.

Accepted Answer

Proportioning valves distribute the brake force between the front and rear brakes, which reduces the risk of wheel lock-up and improves stability during braking. This is usually done by reducing the pressure to the rear brakes to prevent them from locking up under heavy braking, while still providing enough force to slow down the vehicle.

Question 10

An output piston that is larger than the input piston can increase the input force.

Accepted Answer

When the output piston is larger than the input piston, it creates a mechanical advantage, allowing the same input force to produce a greater output force. This is based on the principle of Pascal's law, which states that pressure applied to an enclosed fluid is transmitted equally in all directions.

Question 11

Two technicians are discussing disc brakes. Technician A says that disc brake pads are much smaller than drum brake shoes. Technician B says that more hydraulic force is needed to stop a disc brake vehicle. Who is correct?

Accepted Answer

Disc brake pads are smaller than drum brake shoes, and more hydraulic force is needed to stop a disc brake vehicle.

Question 12

Two technicians are discussing disc brake calipers. Technician A says that sliding calipers work similar to a wheel cylinder except the caliper can move as a unit. Technician B says that fixed calipers have a minimum of five pistons. Who is correct?

Accepted Answer

Technician A is correct in stating that sliding calipers work similarly to a wheel cylinder, but they are able to move as a unit. Technician B is incorrect in stating that fixed calipers have a minimum of five pistons. Fixed calipers can have anywhere from one to six pistons, and sometimes even more.

Question 13

Two technicians are discussing hydraulic theory. Technician A says that liquids cannot be compressed and make ideal transmitting agents when contained in sealed systems . Technician B says that when pressurized, the temperature of liquids increase. Who is correct?

Accepted Answer

Technician A is correct as liquids are generally considered incompressible and therefore make ideal transmitting agents when contained in sealed systems. 
Technician B is also correct as when liquids are pressurized, the molecules become more tightly packed and move faster, resulting in an increase in temperature.

Question 14

Some drum brakes have a form of self-adjuster to move the brake shoes outward as they wear.

Accepted Answer

Some drum brakes have a self-adjusting mechanism designed to move the brake shoes outward as they wear, ensuring consistent and reliable braking performance over time.

Question 15

Brake fluid should have a minimum boiling point of 200 degrees Fahrenheit.

Accepted Answer

Brake fluid should have a minimum boiling point much higher than 200 degrees Fahrenheit to prevent vapor lock; typical minimum boiling points are around 401 degrees Fahrenheit (205 degrees Celsius) for DOT 3 fluid.

Question 16

Tires are considered to be part of the braking system.

Accepted Answer

Tires are part of the vehicle's suspension system, providing traction between the vehicle and the road surface, but they are not considered components of the braking system, which consists of parts like brake pads, rotors, calipers, and the master cylinder.

Question 17

What characteristic is true of traction control systems?

Accepted Answer

Traction control systems are designed to redirect power from a spinning drive wheel to a non-spinning wheel in order to maintain traction and stability while driving.

Question 18

Brake boosters have a check valve to retain vacuum in case of an engine shutdown.

Accepted Answer

Brake boosters use vacuum from the engine to assist with braking. The check valve retains vacuum in case of an engine shutdown so that the brakes can continue to operate even without engine power.

Question 19

The brake pedal is connected to the master cylinder's piston with a(n) _____.

Accepted Answer

The brake pedal is connected to the master cylinder's piston through a pushrod. When the brake pedal is pressed, it pushes the pushrod which then activates the piston in the master cylinder to create hydraulic pressure that gets sent to the brakes.

Question 20

Bearing races serve the same purpose as the journal.

Accepted Answer

Bearing races serve as the surface against which the bearings rotate, just like a journal in a machine.

Quiz 10: Brakes Systems