Not much to the hydraulic system that cannot be
easily fixed.
First do as Tom suggests. Take off the right
side inspection plate and take a looksie. You
will see to 3/4" vertical arms. This is the
control fork. As you move the lift lever back
and forth you should see these arms move.
Feel down the arms into the oil at the end is a
cup 1/4" in diameter that holds a cross-piece
"yoke" that connects the two arms. In the
middle of this yoke is an axial pin that goes
to the control valve. This is the area Tom is
discussing.
couple of possibilities here. 1) yoke has
popped out of the cups. Just re-hook back up.
2) The yoke to the control valve pin has
separated. Repair as needed (new cotter pin?)
Another possibility is the Pressure relief
valve has stuck open. This just needs the PR
valve replaced. To check start tractor and
engage PTO. Keep your finger out and look for
oil swirling between the control for arms.
Also at this time look for any oil leaks or
dripping/ streams coming from above in the
hydro cover.
If you find anything out let us know and we'll
go from there.
Jeff
top picture shows the control valve connected to the yoke bottom right side, and the yoke/control valve exploded view in the box at the bottom. The second picture shows the control fork with the yoke in the fork cups, right side. The pump is removed.