Tractor Repair: Long 350 fuel pump, proper fuel, orings

Question
Arnie, I have an early 70's model Long 350 tractor with a leaking fuel pump.  This leaking started a couple of years ago with intermittent drops and gradually got to where it seemed to laaek as much as it burned.  The engine continued to run fine up until the last time I ran it.  I suspect that the source of the leak allowed air to be drawn into the fuel system and caused the engine to die.  I have been able to pull-crank the tractor, but it will not remain running.  I am fairly mechanically inclined and am considering rebuilding the fuel pump - I am hoping that only entails new seals and orings.  Do you have any warnings or advice on rebuilding this pump?  I am aware of the timing requirements and the fact that the pump operates under very high pressure.  Any assistance you can offer would be greatly apprecaiated.

Answer
Hello,

  I recommend that an injection pump only be repaired by a diesel injection repair facility.  Not only do they have the necessary equipment and tools to properly repair it, but also to test run it and calibrate it for proper fuel delivery.  The pump may have to be completely disassembled to replace the leaking seals.  Sometimes you can exchange yours for a rebuilt one and don't have to wait for yours to get fixed.  Also, I doubt that you could even obtain the parts that you need to fix it yourself.  The last time I attempted to repair a pump myself, there were no more parts that could be ordered through the machinery dealer.  I could only get a complete remanufactured pump.