You pump the pedal three times and hold it down for five seconds, making sure that the pedal does not move. What are you inspecting?

If your vehicle has hydraulic brakes, test them by pumping the brake pedal three times and then applying firm pressure to it for five seconds, making sure the pedal does not move during that time. If your vehicle has air brakes, test them by performing the final air brake check as described in the CDL manual.