C - Truck/Tractor Air Brake System Components - Part B

Question 1

Spring brake chambers apply and hold a parking brake application:

Answer 1

Without air pressure.

Question 2

Caution must be exercised when working around spring brake equipped vehicles because:

Answer 2

Spring brakes contain large, powerful springs.

Question 3

Air supply for parking/emergency brake operation flows through a double check valve so that the emergency brakes will:

Answer 3

Not apply if either service reservoir air pressure is lost.

Question 4

The function of the park control valve is to provide manual:

Answer 4

And automatic control of all the parking/emergency brakes on the unit.

Question 5

A quick release valve is often used in parking/emergency brake circuits to provide quick:

Answer 5

Application of the spring brakes.

Question 6

An anti-compounding double check valve is often used in parking/emergency brake circuits to:

Answer 6

Release the parking/emergency brakes when the service brakes are applied.

Question 7

Some truck/tractor units are equipped with a spring brake valve that:

Answer 7

Allows the spring brakes to modulate application if primary service reservoir air pressure is lost.

Question 8

A relay valve is used in parking/emergency brake circuits that use spring brake valves to ensure that the spring brakes:

Answer 8

Apply and release quickly.

Question 9

The purpose of the trailer supply line is to transmit air pressure:

Answer 9

To charge the trailer reservoirs.

Question 10

The purpose of the trailer service line is to transmit air pressure:

Answer 10

To apply and release trailer service brakes.

Question 11

The trailer supply valve supplies air pressure to the trailer from:

Answer 11

Both primary and secondary reservoirs.

Question 12

In the event that pressure in both primary and secondary reservoirs falls below 50 psi (345 kPa) the:

Answer 12

Trailer supply valve will close off supply air pressure to the trailer, trailer emergency brakes will apply, and tractor protection valve will close the trailer service line.

Question 13

The purpose of the trailer brake control valve is to allow the operator to:

Answer 13

Independently control trailer service brakes.

Question 14

If the operator makes a 20 psi (138 kPa) application with the trailer brake control valve while making a 10 psi (69 kPa) application with the dual-cicruit brake valve:

Answer 14

Tractor brakes will be applied with 10 psi (69 kPa) and trailer brakes are applied with 20 psi (138 kPa).

Question 15

Tractors equipped with a bobtail proportioning relay valve will reduce:

Answer 15

Primary application pressure when the tractor is not towing a trailer.

Question 16

The brake light switch is normally:

Answer 16

Open switch that is closed by primary or secondary service pressure.