Mercedes Benz repair: diesel injection pump, fuel gauge, diesel injection

Question
I own a 1978 mercedes--240D.  My car stopped running on me.  My fuel gauge doesnt work, but I put about 4 gals. of diesel in it.  My inline fuel filter is dry.  I tried pumping the little primer pump but i get no diesel to the filter.  I also cranked it but to no avail.  Does this mean that my injection pump is out?  Please advise.  

best regards
Rick Carranza

Answer
No it means there is air in the lines. You need to crack a line at the injector then prime the pump. It takes a lot to pump fuel to the injectors. You really have to pump vigorously for several minutes. Watch for fuel coming out of the line. As soon as you see fuel close it back up and start the car.