Slim, John is right on all counts above. If a single action cylinder is full (up) and your resivoir is full (on the dipstick), then when you let the haybine down, it pushes the cylinder oil back to your resivoir causing an overfull condition. The only place it can go is out the fill cap. These resivoirs are small and don&#039;t have a lot of space for extra oil.
  oleblu