Air brake Quiz #1

Question 1

Reaction time maybe defined as:

the time it takes for the driver to push the treadle valve.

the time it takes for the vehicle to stop after the treadle valve has been depressed.

the time it takes for the air to reach the brake chamber from the treadle valve.

the time it takes for the driver to adjust the brakes.

Answer 1

the time it takes for the driver to push the treadle valve.

Question 2

Brake lag is:

the time it takes for the driver to push the treadle valve.

the time it takes for the driver to adjust the brakes.

the time it takes for the vehicle to stop after the brakes have been applied.

the time it takes for the air to reach the brake chamber from the treadle valve.

Answer 2

the time it takes for the air to reach the brake chamber from the treadle valve.

Question 3

If the speed of a truck were doubled; the amount of work the brakes would have to do would be:

8X

the same as before.

4X

2X

Answer 3

4X

Question 4

A vehicle requires 400 hp (149kw) to accelerate from 0 to 100Km/hr in 60 seconds. To bring the same vehicle to a complete stop in 6 seconds, the braking system must develop:

200 hp (149kW).

400 hp (300kW).

2000 hp (1.49MW)

4000 hp (3.00MW).

Answer 4

4000 hp (3.00MW).

Question 5

To protect the air brake system from excess pressure, the pressure relief valve will relieve at:

150 p.s.i.

300 p.s.i.

120 to 130 p.s.i.

175 p.s.i.

Answer 5

150 p.s.i.

Question 6

Moisture forms in the reservoirs by:

evaporative cooling.

pressurizing the air.

evaporation.

condensation.

Answer 6

condensation.

Question 7

The standard for pressure in an air brake system in Alberta is:

175 p.s.i.

120 – 130 p.s.i.

150 p.s.i.

100 – 120 p.s.i.

Answer 7

120 – 130 p.s.i.

Question 8

Normal lag time on a well maintained air brake system is approximately:

.7 seconds.

.3 seconds.

1.3 seconds.

.25 seconds.

Answer 8

.3 seconds.

Question 9

Most air brake valves in the released position will have:

both valves open.

both valves closed.

the exhaust valve open.

the inlet valve open.

Answer 9

the exhaust valve open.

Question 10

The coefficient of friction maybe defined as:

how hard the brake linings are.

how much heat the linings and drums produce.

all of the above.

the resistance to movement between the shoes and the drums.

Answer 10

the resistance to movement between the shoes and the drums.

Question 11

Very high temperatures cause the numerical value for the coefficient of friction of the brake pad to:

improve.

increase.

decrease.

remain the same.

Answer 11

decrease.

Question 12

One disadvantage air brake systems have is that:

braking effort is affected by small leaks in the system.

the system must be bled when connecting or disconnecting the system.

air brake components are more expensive than hydraulic components.

there is always some brake lag.

Answer 12

there is always some brake lag.

Question 13

A driver makes a 40 p.s.i. application. If the vehicle is equipped with air brake chambers that are type 30; each chamber will exert:

1200 lbs. of force.

120 lbs. of force.

3600 lbs. of force.

2400 lbs. of force.

Answer 13

1200 lbs. of force.

Question 14

The part of the air brake system that the driver uses to regulate the air pressure when applying the brakes, is the:

brake chamber.

brake valve.

slack adjuster.

governor.

Answer 14

governor.

Question 15

The inventor of the air brake is credited as being:

Westinghouse.

Meritor-Wabco.

Haldex.

Bendix.

Answer 15

Westinghouse.

Question 16

A properly adjusted brake will have:

a slight amount of drag.

2 inches of travel with no drag.

1 inch of travel with no drag.

1 inch of travel with a slight drag.

Answer 16

1 inch of travel with no drag.

Question 17

Brake drums are marked with:

a minimum thickness.

discard circumference.

an out of round spec..

a maximum diameter.

Answer 17

a maximum diameter.

Question 18

One important rule when working on the foundation brake system, is to:

avoid inhaling brake dust.

clean brake shoes thoroughly with compressed air.

watch for released springs.

always replace drums.

Answer 18

avoid inhaling brake dust.

Question 19

Using brake lining with a GAWR that is too low can result in:

brake fade.

decreased stopping distance.

no effect on the braking.

greater brake application pressure.

Answer 19

brake fade.

Question 20

Air brake systems are usually referred to as:

forward acting.

single servo.

non-servo.

duo-servo.

Answer 20

non-servo.

Question 21

Brake fade maybe defined as:

brake slippage when below freezing.

brake slippage when they are overheated.

brake grabbing when they are overheated.

brake slippage due to thin linings.

Answer 21

brake slippage when they are overheated.

Question 22

The component that provides support for most of the components in the foundation brakes is called:

brake plate.

brake foundation.

brake drum.

brake spider / backing plate.

Answer 22

brake spider / backing plate.

Question 23

Brake travel is measured between:

the brake shoe and drum.

the brake chamber diameter.

the brake shoe and the drum.

the brake chamber and slack adjuster.

Answer 23

the brake chamber and slack adjuster.

Question 24

When we look for a 90° angle, we are looking for that angle between:

the brake shoe and drum.

the brake spider and slack adjuster.

the brake chamber and s-cam.

the brake chamber and slack adjuster.

Answer 24

the brake chamber and slack adjuster.

Question 25

Flat brake cams are often used in steer axle applications because they:

have a slower rate of application than s-cams.

have a quicker rate of application than s-cams.

require less air to operate.

are more resistant to fade.

Answer 25

have a slower rate of application than s-cams.

Question 26

The automatic slack adjuster automatically makes a brake adjustment when:

the brakes are released.

a mechanic adjusts them.

the clearance between the lining and drum is to close.

an application is made.

Answer 26

the brakes are released.

Question 27

The caliper of an air disc brake must be able to slide on its mounting pins so that:

the inboard brake pad contacts the rotor.

the brake pad piston has sufficient clearance.

the caliper can be cooled.

the outboard brake pad contacts the rotor.

Answer 27

the outboard brake pad contacts the rotor.

Question 28

The advantage of air disc brakes is that they:

are lighter.

are more efficient.

are more fade resistant.

react more quickly.

Answer 28

are more fade resistant.

Question 29

The term balanced braking means that:

each axle and wheel of the unit bears only a proportion of the total load which it was designed to carry.

each brake is applied at the same low air pressure and does the same proportion of the total braking as it carries the total weight of the unit.

the trailer brakes maybe applied independently of the tractor brakes.

when pressurized the brakes exhaust air only when the parking brake is set or if a break or serious leak occurs in the system.

Answer 29

each axle and wheel of the unit bears only a proportion of the total load which it was designed to carry.