I have a GB diesel with a american bosch injection pump. The tractor had been setting for a while and when I went to start it I could not get any fuel to the injectors. I then primed and bleed all the lines but still nothing. I have had these pumps freeze up before so I lubed it up and finaly got the delivery valve moving a little but it doesn't seem to go through the complete travel. The plunger sleeve does not seem to go all the way up to close off the hole, therefore it will not build pressure. It seems to get stuck and will not come off the kill position. What should I do next? Take off the head of the pump and look for trash or burrs on the sleeve? Any help would be appreciated.