Are you sure the problem is that the injection pump needs bleeding?
One way is to break lose the line going from the pump to the injectors ... this can be done at the injector or the pump, however, at the injector will bleed the lines more fully.
You will need a fully charged battery. Turn the tractor over until you see fuel start to drip/spray/run out of the lines (what it does will depend on how lose you made them - the loser they are the quicker it will bleed)
Once fuel shows, tighten them one at a time. This can be done without starting the tractor - it can also be done if you let the tractor start (or try to) and tighten them as they fire. The tractor will not run smoothly until they are all tightened.