Air Brakes

Question 1

What is a foot valve responsible for (3 things) as well as list its other name?

Answer 1

The treadle Valve:

1. Foot pedal Feel
2. Actuating pressure to relay circuit
3. Acts as the relay piston

Question 2

Another name for a two way check valve

Answer 2

A shuttle valve

Question 3

What circuit locks out the inversion valve?

Answer 3

The primary Circuit

Question 4

Two types of automatic slack adjusters

Answer 4

Clearance, Stroke

Question 5

what are rotochambers used for?

Answer 5

Off road applications

Question 6

what are two purposed of a slack adjuster?

Answer 6

To spline to s-cam or wedge to adjust slack,

To act as a lever

Question 7

What is a trailer application valve?

Answer 7

(Known as broker break/ spike) actuates and engages the trailers breaks.

Question 8

What is a relay valve?

Answer 8

Remote control valve (uses 25 psi to trigger use) used to reduce break application and release times (crack pressure change).

Question 9

Crack pressure

Answer 9

The required pressure to actuate so it can start to meter air.

Question 10

Quick release valves

Answer 10

Help speed the exhausting of air from a circuit, tends to have one inlet and two outlets.

Basically used to just release excess air in a circuit instead of having it go back to the source valve.

Question 11

Ratio Valve

Answer 11

Limits front axle breaking under light and medium applications.
The valve wont crack unless it goes over 10, 10-40 psi is 50% APPLIED, while 60 psi is 100% Applied

Question 12

Inversion Valves

Answer 12

Improves breaking under emergency conditions,
Informs the foot valve (treadle) to send a signal to ease off the air in the spring breaks to help effect and emergency stop.

Question 13

Bobtail proportioning valve

Answer 13

Designed to help reduce normal break service application pressure anytime the tractor isn’t connected to a trailer. (During bob tailing mode the front brakes receive full breaking pressure).

Question 14

Tractor Protection valves

Answer 14

First: acts as a means of routing and switching the trailer air supply and trailer service from the tractor.

Second: Protects tractor air supply in the event of a trailer breakaway or total air loss

Question 15

What are stop lamp switches?

Answer 15

it is used to illuminate the brake lights on the vehicle. rated by how much air pressure it takes to close the circuit.

Question 16

Brake chamber are?

Answer 16

They are used to convert air pressure into mechanical force to stop a vehicle
Components: Diaphragm, Retraction spring, and pushrod

Question 17

What are long stroke chambers?

Answer 17

used to produce longer strokes by increasing the distance between the pressure and non pressure plates of the chamber.

Question 18

Name all six brake imbalance terms?

Answer 18

1. Brake torque imbalance,
2. Jackknife,
3. trailer swing,
4. plow-out,
5. pneumatic timing,
6. Pneumatic balance

Question 19

Split-Coefficient stops

Answer 19

helps balance vehicle if the vehicles one side is on ice while the other is on pavement
Helps maintaining maximum road traction

Question 20

What is the difference between park on air and park on spring trailer brakes?

Answer 20

Park on air: Brake chambers charged with air

Park On spring: Brake chamber mechanically actuated (springs on)

Question 21

What are the shapes and colours of the System Park Valve, Trailer supply valve and tractor park valve?

Answer 21

1. System Park valve: Diamond and Yellow shaped ) (When pulled out bother other brakes are pulled out as well and placed into park)
2. Trailer supply valve: Octagonal and red (when pushed in 60 psi is used to hold off spring brakes)
3. Tractor Park Valve: Round an blue

Question 22

Two devices used on foundation brakes:

Answer 22

S-cam and wedge

Question 23

What is DD3 chambers used for?

Answer 23

In transit and intercity buses

Question 24

Where are the LED’s located on a bendix ABS modulator controller assembly?

Answer 24

On the Controller assembly

Question 25

What part of the air compressor is controlled by the governor?

Answer 25

The unloader and unloader pistons