In the event of hydraulic brake failure, which of the following should you NOT do?

In the situation of hydraulic brake failure, shifting up is not advisable because it does not effectively help in controlling the vehicle or reducing speed. When hydraulic brakes fail, the driver needs to take immediate action to slow down or stop the vehicle. Shifting up could cause the vehicle to accelerate if the engine is not already under strain, which would be counterproductive in a braking emergency.

Other actions, such as shifting down, using the parking brake, and pumping the brake pedal, are standard procedures in managing brake failure. Shifting down helps to utilize engine braking, which can slow the vehicle more effectively. Using the parking brake provides a backup method to slow down, and pumping the brake pedal may help regain some brake pressure in certain conditions. Therefore, these actions are effective in responding to hydraulic brake failure, making shifting up the least appropriate option.