I finally got around to fixing the Henderson loader on my Farmall M. Oil was pouring out the vent hole on the top of one cylinder and the pump was only lifting the bucket a little bit at a time. Fixing the cylinder seal was not hard-- $13. I put a used pump on there from a retired farmer who said it worked when removed. Now it lifts about a foot at a time-- if you keep sort of pumping the lever it will lift it all the way up but this doesn't seem to be how it should work. I added more 30 weight oil and it worked a little better but I am concerned about overfilling-- those cylinders have a lot of space in them-- maybe I just need more oil or is this a symptom of overfilling or just another somewhat shot pump?