The BMW 520i uses an electric fuel pump, mounted at the rear of the car next to the fuel tank.
Removing both mechanical and electric fuel pumps is not particularly difficult.
Fuel pump for BMW engines "518", "520":
1 - pusher; 2 - heat-insulating gasket; 6 — pump body.
Fuel pump parts for BMW "525" and "528" engines:
6 - pusher; 10 — pump body; 18 — diaphragm; 20 — pump cover.
This publication was borrowed from an online resource: BMWMAN.RU