If for some reason you need to dismantle the (mechanical) gas pump of your classic car, replace the fuel lines, it is useful to know if that part is mounted lower than the gas tank. Due to gravity you will otherwise get a tsunami of extremely flammable liquid on the floor of your (wet) shed, garage, garden path, sidewalk or street. One spark or a burning (gas) heater can turn the key festival into an inferno. If the gas pump needs to be replaced, then 'pinch' the pipe with a commercially available tool. If the flexible pipes need to be replaced (that is wise because of the miserably poor and aggressive quality of today's petrol), it is advisable to virtually empty the tank. Remember, with such a job no sparks, no open fire, because 'something' is always spilled. You do the tinkering for your own account and risk.
Can someone tell me how exactly the petrol pump on an antique car works? For the sake of clarity, this is one that works by means of the outlet or inlet manifold.