Revision question · Vehicle condition

Why do air tanks on brake systems need to be drained?

Revision material from the imported DVSA bank includes source-checked Lanekind learning corrections. These corrections are not newly issued official examination questions, and practice does not reproduce a live test paper.

Answer options

To remove excess coolant

To remove rain water that's seeped into the system

To remove any oil leaks that collect here

To remove moisture drawn in from the atmosphere

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To remove moisture drawn in from the atmosphereThis was the right answer

Moisture in the air condenses as the air pressure increases. This moisture can be transmitted around the braking system and is especially dangerous in cold weather. It can lead to ice forming and blocking the valves and pipes.

Reviewed reading for this question

Match reservoir draining to the fitted air systemReviewed guidance summary · The manual-drain question is explicitly scoped; dryer and automatic-drain systems follow their own schedules.

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