A brake check or brake test is when the driver deliberately hits the brakes to test them.

Given F1 cars don’t have brake lights this action needs to be performed only when there are no cars close behind. Otherwise, the stewards may rule that it is considered dangerous driving and issue a warning or a penalty. 

Drivers have been known to test their brakes to catch out the car behind “He just ‘brake checked’ me” 

Andrew Burden

The author Kiwi F1 Fan