Trainee bus driver and instructor reviewing a checklist beside a single-deck bus at the depot

PCV study notes

Braking Systems

Air brakes, ABS, endurance brakes, brake fade, maintenance and freezing conditions.

What this topic covers

Air brakes, ABS, endurance brakes, brake fade, maintenance and freezing conditions. The full PCV Theory Test & Toolkit app contains 45 questions on this topic.

In the app's syllabus: Types of brake, Maintenance and inspection, Connection & proper use of the brakes, Tailgating, Freezing conditions, Anti-lock brakes.

Worked examples

Here are a few practice questions from this topic. Try answering each before reading the explanation.

Example 1

How can you help to prevent 'brake fade'?

A. Use the endurance brake ✓ correct
B. Apply the parking brake
C. Select neutral for a short distance
D. Repeatedly pump the brake pedal

Explanation: Brake fade occurs when the brakes overheat. Good forward planning and correct use of the gears when descending hills, together with proper use of the endurance brake (retarder), can help to prevent brake fade.

Example 2

What's the most powerful brake on a bus?

A. Secondary brake
B. Anti-lock braking system
C. Endurance brake (retarder)
D. Service brake ✓ correct

Explanation: The most powerful and effective brake on the vehicle is the service brake, and this should be used in normal circumstances. Well-maintained brakes should apply an even pressure to all the wheels, providing an efficient, controlled stop.

Example 3

You're driving a vehicle fitted with anti-lock brakes. What should you do when braking in an emergency?

A. Apply firm, continuous pressure to the brake pedal ✓ correct
B. Use the exhaust brake (retarder) before the footbrake
C. Apply minimum force to the brake pedal
D. 'Pump' the brake pedal harshly

Explanation: Applying a firm, continuous brake pressure will allow the anti-lock braking system (ABS) to function properly. However, ABS is becoming increasingly sophisticated, so you should read the vehicle manufacturer's handbook for its advice about using the system.

Example 4

'Brake fade' is a loss of effectiveness of the brakes when they overheat. When would 'brake fade' be most likely to happen?

A. On a long uphill gradient
B. On the approach to hazards
C. On a long downhill gradient ✓ correct
D. On a long journey

Explanation: Continuous use of the brakes will cause them to overheat, and in extreme cases they'll become ineffective. When you're going downhill, the momentum of your vehicle will cause you to gather speed very quickly. Use the endurance brake (retarder) and stay in a low gear to reduce the need to use the brakes.

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More PCV study notes

Get all 45 questions on this topic in the PCV Theory Test & Toolkit app.