Just bought a Dewalt 120 volt impact gun. Used it to remove the wheels from my 3500 Sprinter class C. Also used it to remove the bolts holding the brake rotors on same vehicle.
120 volts always available from genset or inverter in camper.
The electric impact does hammer for a few seconds, up to 15 seconds on a hard bolt. It does the job. The brakes on the New to Me camper were original, never changed.
I will never be without one again. The motor does not put out that many footpounds, the torque is developed by the hammer on the anvil.