First of all, I'm not a mechanic, but I was able to install these hubs without a percussion gun. You will need to use force and leverage with a pry bar and a short punch extension to loosen the (4) 17mm screws. Do not attempt to use the steel extension provided with the ratchet. the required angle and torque will break them. Being perfect for the originals, they deaden the rumble of the old jacks. Good business