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

The brake rotor directly

The brake pads without linkage

The air compressor piston

The slack adjuster attached to the end of the camshaft

2 / 25

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

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

Rotors, calipers, brake pads and slack adjusters

Calipers, spiders, rollers and anchor springs

Drums, rotors, pads and compressors

3 / 25

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

The exposed pushrod

The lack of external components

A sealed pushrod with no exposure

The built-in hydraulic assist

4 / 25

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

Camshaft rollers

Anchor springs

Brake spider inside the drum

Brake chamber and mounting brackets

5 / 25

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

It cools the brake drum

It serves as the main mounting base for the brake shoes

It stores emergency air

It meters air pressure to the brake chamber

6 / 25

Which key components are common to disc air brakes?

Compressors, tanks and valves

Drums, shoes, rollers and spiders

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

Wedges, anchor pins and return springs

7 / 25

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

It keeps the brake chamber pressurized when parked

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

8 / 25

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

Support brackets and bushings for the camshaft

Anchor pins and anchor springs

Wedge and shoe guides

Brake pads and caliper

9 / 25

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

The cab-mounted brake controls

The air compressor and governor

The air tanks and valves

The brake-assembly components at the wheels

10 / 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 used only during emergency braking

They are made of concrete-like material

11 / 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

Electric brakes, hydraulic brakes, and vacuum brakes

Drum brakes, parking brakes, and engine brakes

12 / 25

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

It forces a wedge between the brake shoes

It presses the brake pads against the rotor

It releases the caliper from the rotor

It turns the rotor faster

13 / 25

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

Rotates an “S” cam to move the shoes

Releases the parking brake only

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

Squeezes calipers onto a rotor

14 / 25

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

They may be covered by a dust shield or backing plate

They are above the frame rails

They are painted black

They are inside the cab

15 / 25

What is the main function of foundation components?

They control the trailer’s lights and signals

They measure tire pressure

They generate compressed air for the system

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

16 / 25

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

They monitor wheel speed

They support the brake chamber

They lubricate the brake linings

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

17 / 25

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

They cannot be adjusted

They must be adjusted manually every day

They are designed to be self-adjusting

They use external slack adjusters

18 / 25

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

It releases the parking brake only

It increases air pressure in the reservoir

It turns on a warning light

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

19 / 25

How many types of foundation brake systems are?

Three

Four

Five

Two

20 / 25

The “S” cam brake is a type of:

Disc brake

Drum brake

Wedge-less brake

Electric brake

21 / 25

The wedge air brake system is a type of:

Electric brake

Drum brake

Disc brake

Hydraulic brake

22 / 25

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

Wedge brake

“S” cam brake

Disc brake

Hydraulic drum brake

23 / 25

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

They are mounted outward, away from the wheel

They are mounted vertically above the axle

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

They are mounted parallel to the frame rails

24 / 25

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

Reduce friction between drum and shoes

Increase air pressure in the brake chamber

Control brake light operation

Hold the brake shoes in position at the anchor end

25 / 25

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

It is not used in air brake systems

It is mounted inside the cab

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

It is completely visible from outside the vehicle

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.