LGV Braking Systems

Question 1

What is the minimum efficiency required for the service brake on an HGV at its annual test?

Accepted Answer

50%

Answer

25%

Answer

43%

Answer

60%

Question 2

What is the function of the spring brake on an HGV?

Accepted Answer

To apply the parking brake using powerful springs when air pressure is released

Answer

To provide additional speed

Answer

To assist with steering

Answer

To support the suspension

Question 3

What happens to the braking system if the air compressor fails on an HGV?

Accepted Answer

The air pressure drops and eventually the spring brakes automatically apply, stopping the vehicle

Answer

Nothing — the brakes work without air

Answer

The vehicle speeds up

Answer

Only the trailer brakes are affected

Question 4

What is the purpose of the brake pressure warning indicator?

Accepted Answer

To alert the driver when air pressure in the braking system drops below a safe level

Answer

To show when brakes are working perfectly

Answer

To indicate the brake pad thickness

Answer

To show outside temperature

Question 5

What is the function of the load sensing valve (LSV) in the braking system?

Accepted Answer

To automatically adjust brake pressure based on the vehicle's load, preventing wheel lock on lightly loaded axles

Answer

To sense the temperature of the brakes

Answer

To count the number of brake applications

Answer

To regulate the air compressor speed

Question 6

How does an exhaust brake work on an HGV?

Accepted Answer

It restricts the exhaust flow, creating back-pressure that uses the engine as a retarder to slow the vehicle

Answer

It applies pressure to the exhaust pipe

Answer

It releases exhaust gas onto the road surface for grip

Answer

It increases exhaust emissions to slow down