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

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

The exposed pushrod

A sealed pushrod with no exposure

The lack of external components

The built-in hydraulic assist

2 / 25

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

It stores emergency air

It cools the brake drum

It serves as the main mounting base for the brake shoes

It meters air pressure to the brake chamber

3 / 25

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

Calipers, spiders, rollers and anchor springs

Drums, rotors, pads and compressors

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

Rotors, calipers, brake pads and slack adjusters

4 / 25

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

Hydraulic drum brake

Wedge brake

“S” cam brake

Disc brake

5 / 25

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

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

They support the brake chamber

They lubricate the brake linings

They monitor wheel speed

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

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

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

They are mounted parallel to the frame rails

8 / 25

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

Increase air pressure in the brake chamber

Control brake light operation

Hold the brake shoes in position at the anchor end

Reduce friction between drum and shoes

9 / 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

10 / 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

11 / 25

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

They are inside the cab

They are painted black

They may be covered by a dust shield or backing plate

They are above the frame rails

12 / 25

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

It releases the caliper from the rotor

It forces a wedge between the brake shoes

It turns the rotor faster

It presses the brake pads against the rotor

13 / 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

14 / 25

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

They must be adjusted manually every day

They are designed to be self-adjusting

They use external slack adjusters

They cannot be adjusted

15 / 25

The “S” cam brake is a type of:

Wedge-less brake

Disc brake

Drum brake

Electric brake

16 / 25

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

Releases the parking brake only

Squeezes calipers onto a rotor

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

Rotates an “S” cam to move the shoes

17 / 25

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

Brake chamber and mounting brackets

Camshaft rollers

Anchor springs

Brake spider inside the drum

18 / 25

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

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

It holds the brake pads against the rotor at all times

It keeps the brake chamber pressurized when parked

It increases force on the brake shoes during application

19 / 25

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

The slack adjuster attached to the end of the camshaft

The brake pads without linkage

The brake rotor directly

The air compressor piston

20 / 25

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

Front brakes, rear brakes, and trailer brakes

Drum brakes, parking brakes, and engine brakes

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

Electric brakes, hydraulic brakes, and vacuum brakes

21 / 25

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

Brake pads and caliper

Wedge and shoe guides

Anchor pins and anchor springs

Support brackets and bushings for the camshaft

22 / 25

The wedge air brake system is a type of:

Drum brake

Disc brake

Electric brake

Hydraulic brake

23 / 25

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

It increases air pressure in the reservoir

It releases the parking brake only

It turns on a warning light

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

24 / 25

What is the main function of foundation components?

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

They generate compressed air for the system

They measure tire pressure

They control the trailer’s lights and signals

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.