The only major problems with this type of fuel pump was if the diaphragm went bad or got a hole in it. If this happened, the pump could just stop working, or it could pump gas out the side of the pump. Well, this is the third thing that a mechanical fuel pump can do if the diaphragm goes bad. Instead of pumping gas out of the pump, it can pump gas directly into the oil pan. Newer model cars use electric fuel pumps.
Some models even have two pumps, one is the supply pump, and the second is the pressure pump.
If the vehicle has two pumps, the supply pump will be mounted inside the gas tank, and the pressure pump will be mounted on the frame close to the engine. If your car has only one pump it will be mounted inside the gas tank. The relay operates the pump. When the electric pump runs, it pushes fuel through the fuel filter and up to the fuel pressure regulator. Now the fuel filter is the most important part of the system.