Tractor Repair: 1970 Case 1370 Fuel Line Leak, rubber compression, line leak

Question
The problem is when it is running where the injector hooks onto the line, it leaks fuel.  I can't tell where it leaks.  I have replaced the line and gaskets on the line.  Could it be a bad injector or a hole in it?  What is the best way to go at this problem?  Thanks for any help that you may be able to offer.

Answer
  It would be extremely unlikely that the injector itself would leak.  There are 3 places that they usually leak.  Where the injection line from the pump attaches, where the return lines attach to the tee fitting on top of the injector, and where the tee fitting attaches to the injector.  Make sure the fitting for the injection line is tight and that the line is not cracked and has not been rubbing against something.  The short tubes between the injectors are the return lines and are probably the most likely thing to leak.  There are rubber sleeves on the end of the tubes that compress when the nut is tightened onto the tee fitting.  There is also a rubber compression sleeve and nut where the tee fitting is attached to the top of the injector.  If you have already replaced the seals on the tubes, then possibly this seal on the tee fitting is leaking.