What must be set before pumping to prevent unintended vehicle movement?

• A. Emergency warning switch
• B. Parking brake
• C. Auto ignition switch
• D. Transmission clutch

Answer: (B)

Setting the parking brake before pumping is the best way to keep the rig from moving. When you start the pump and operate lines, torque and vibrations can cause the vehicle to creep or roll if the brakes aren’t holding. The parking brake engages the wheel brakes to lock the vehicle in place, providing a secure restraint on flat or sloped ground so you can work safely. The other options don’t provide this restraint: the emergency warning switch is for signaling, the auto ignition switch starts the engine, and the transmission clutch isn’t the standard method used to hold an apparatus stationary during pumping.