zetor crystal 8011 diesel pump leak

[greendragon3]

hi zetor kings , my 8011 has a fairly bad diesel leak on the top of the injector pump , i thought the air bleed screw was the culprit so i took it off and cleaned it and gave it a new copper washer but it is still pissing out diesel somewhere , it looks to be around the injector pipes themselves but they all seem to be tight , when the tractor is running it is hard to see exactly where it is coming from as the fan is blowing the excess diesel back along the top of the pump making it impossible to diagnose where the leak is coming from , it has no effect on the performance of the tractor and it doesn't cause it to air lock or anything it is just messy on what is otherwise a very dry clean engine , has anyone ever had any experience of something like this or do you have any advice as to stripping these pumps etc ???