Chapter 6: Foundation Brakes

The “Foundation Brakes” chapter in the Ontario air brake test guide covers the basic braking mechanisms found on commercial vehicles.

Ontario Air Brake Test - Chapter 6: Foundation Brakes

1 / 25

In a disc air brake system, what does the brake chamber pushrod stroke do?

It turns the rotor faster

It presses the brake pads against the rotor

It forces a wedge between the brake shoes

It releases the caliper from the rotor

2 / 25

Which components support and guide the rotation of the “S” camshaft outside the wheel?

Wedge and shoe guides

Anchor pins and anchor springs

Brake pads and caliper

Support brackets and bushings for the camshaft

3 / 25

What is the role of the return spring in an “S” cam brake assembly?

It holds the brake pads against the rotor at all times

It increases force on the brake shoes during application

It pulls the brake shoes to the released position and keeps the rollers engaged with the camshaft head

It keeps the brake chamber pressurized when parked

4 / 25

In an “S” cam brake, what does the air brake chamber pushrod act on?

The air compressor piston

The brake rotor directly

The brake pads without linkage

The slack adjuster attached to the end of the camshaft

5 / 25

What is usually true about the visibility of the brake rotor in a disc brake system?

It is mounted inside the cab

It is not used in air brake systems

It is only partially visible because the wheel, caliper and dust shields cover parts of it

It is completely visible from outside the vehicle

6 / 25

What is the main function of foundation components?

They generate compressed air for the system

They are the mechanical parts at or around the wheels operated by the air brake system

They control the trailer’s lights and signals

They measure tire pressure

7 / 25

The wedge air brake system is a type of:

Disc brake

Hydraulic brake

Electric brake

Drum brake

8 / 25

What is the brake spider’s function in an “S” cam brake?

It serves as the main mounting base for the brake shoes

It meters air pressure to the brake chamber

It cools the brake drum

It stores emergency air

9 / 25

What do anchor springs do in an “S” cam brake assembly?

Increase air pressure in the brake chamber

Reduce friction between drum and shoes

Hold the brake shoes in position at the anchor end

Control brake light operation

10 / 25

In a wedge brake, what does the stroke of the brake chamber pushrod do?

Rotates an “S” cam to move the shoes

Slides a wedge between the brake shoes, forcing them outward against the drum

Squeezes calipers onto a rotor

Releases the parking brake only

11 / 25

Why are internal “S” cam brake components difficult to see?

They may be covered by a dust shield or backing plate

They are painted black

They are inside the cab

They are above the frame rails

12 / 25

The “S” cam brake is a type of:

Wedge-less brake

Disc brake

Electric brake

Drum brake

13 / 25

Which of the following are the three types of foundation brake systems?

“S” cam brakes, disc brakes, and wedge brakes

Front brakes, rear brakes, and trailer brakes

Drum brakes, parking brakes, and engine brakes

Electric brakes, hydraulic brakes, and vacuum brakes

14 / 25

Why are they called "foundation" components?

They form the basis on which the rest of the brake system is built

They are located in the vehicle’s frame rails

They are made of concrete-like material

They are used only during emergency braking

15 / 25

Which key components are common to disc air brakes?

Compressors, tanks and valves

Rotors, calipers, brake pads, slack adjusters and brake chambers

Drums, shoes, rollers and spiders

Wedges, anchor pins and return springs

16 / 25

What is the result of the pushrod stroke in an “S” cam brake system?

It causes the camshaft to rotate and forces the brake shoes against the drum

It releases the parking brake only

It turns on a warning light

It increases air pressure in the reservoir

17 / 25

Which of the following lists only components of wedge air brakes?

Calipers, spiders, rollers and anchor springs

Drums, rotors, pads and compressors

Rotors, calipers, brake pads and slack adjusters

Brake drums, brake shoes and linings, spiders, dust shields and brake chambers

18 / 25

Which of the following is an external component of an “S” cam brake?

Brake spider inside the drum

Camshaft rollers

Brake chamber and mounting brackets

Anchor springs

19 / 25

What is the purpose of the camshaft rollers in an “S” cam brake?

They lubricate the brake linings

They monitor wheel speed

They support the brake chamber

They rotate with the camshaft while moving the brake shoes inward and outward

20 / 25

What is a key design feature of wedge air brakes regarding adjustment?

They use external slack adjusters

They cannot be adjusted

They must be adjusted manually every day

They are designed to be self-adjusting

21 / 25

Which components at the wheels of a vehicle are generally called the foundation components?

The air compressor and governor

The air tanks and valves

The brake-assembly components at the wheels

The cab-mounted brake controls

22 / 25

What is characteristic of the “S” cam brake design and helps with checking adjustment?

The exposed pushrod

A sealed pushrod with no exposure

The built-in hydraulic assist

The lack of external components

23 / 25

In a wedge air brake system, how are the brake chamber pushrods oriented?

They are mounted parallel to the frame rails

They are mounted vertically above the axle

They are mounted so the pushrods face inward toward the brake shoes and drum

They are mounted outward, away from the wheel

24 / 25

Which type of foundation brake is the most common on commercial vehicles with air brake systems?

Wedge brake

Hydraulic drum brake

Disc brake

“S” cam brake

25 / 25

How many types of foundation brake systems are?

Four

Three

Five

Two

Your score is

It explains the components of foundation brakes, including brake drums, shoes, linings, return springs, and actuators. The chapter details how air pressure is converted into mechanical force to safely stop the vehicle. Understanding the operation, inspection, and maintenance of these components is crucial for ensuring optimal performance and compliance with safety standards. Mastery of this section helps drivers identify wear or damage early, reducing the risk of brake failure. Knowledge of foundation brakes is vital for passing Ontario’s air brake test.