Great Plains 2020 Vintage Drills - Manual (Page 4)

03-01-92 1-4
BLEEDING THE HYDRAULICS
1. Be sure tractor hydraulic reservoir is full.
2. With the markers in field position, crack the hydraulic hose fittings located at the base end of
the cylinder(s). With your tractor at an idle speed, activate your tractor hydraulic’s valve until hy-
draulic oil seeps out around the hose ends. Tighten the hose end fittings and repeat this process
with the hose end fitting(s) located at the rod end of the cylinder(s).
3. Fold and unfold the marker(s) slowly in order to work all the air out of your marker hydraulics.
4. Adjust the speed of the marker with the needle valve, single markers only, to a low setting.
Fold the marker up and down a few times and recheck for pinching and kinking of hoses. Reset
folding speed with the needle valve to a safe speed.
CAUTION! Escaping fluid under pressure can have sufficient force
to penetrate the skin. Check all hydraulic lines and hoses BEFORE applying
pressure. Fluid escaping from a very small hole can be almost invisible. Use
paper or cardboard, NOT BODY PARTS, to check for suspected leaks. If
injured, seed medical assistance from a doctor that is familiar with this type
of injury. Foreign fluids in the tissue must be surgically removed within a few
hours or gangrene will result.
EXCESSIVE SPEED CAN CAUSE MARKER DAMAGE.
!
!
CYCLING THE MARKERS
THE MARKERS CYCLE IN THE FOLLOWING SEQUENCE:
(1) Right Up, Left Up
(2) Right Down, Left Up
(3) Right Up, Left Up
(4) Right Up, Left Down
(5) Sequence Repeats
NOTE: Raising and lowering speed of the markers is due to the internal orifice in the sequence valve necessary for
proper operation of the valve spool.