BMW engines «525» And «528» have a detachable fuel pump. BMW engine electric fuel pump design «520i» and mechanical fuel pump for BMW engines «518» And «520» unbreakable and beyond repair.
Mark the position of the pump cover relative to the housing.
Remove cover and suction valve. Check the operation and technical condition of the discharge valve.
Clean the pump of dirt and flush it with plenty of gasoline.
If the diaphragm is ruptured, replace it. To do this, remove the actuator lever axle, plate, actuator lever and its return spring and diaphragm assembly.
Install a new diaphragm using tool 5125. The diaphragm must be installed horizontally, without distortion, and fit snugly against the body.
Install the pump cover according to the marks made earlier.