Great Plains CPH-20 Predelivery Manual - Manual (Page 8)

6 CPH Center Pivot Hitch 148-152Q 12/28/05
Great Plains Mfg., Inc.
Bleeding the Hydraulics
!
WARNING!
Escaping fluid under pressure can have sufficient force to pene-
trate the skin. Check all hydraulic lines and hoses before apply-
ing 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, seek medical assistance
from a doctor that is familiar with this kind of injury. Foreign
fluids in the tissue must be surgically removed within a few
hours or gangrene will result.
Hydraulics must be bled of air before hitch operation.
Bleed hydraulics during initial hitch setup. If the hydraulics
are not bled, the cylinders will move with jerky, uneven mo-
tions.
Bleeding Tongue Cylinder
1.
Check hydraulic fluid in tractor reservoir and fill to
proper level. Add fluid to system as needed. Tongue
cylinder capacity is one-half gallon (1.89 liters).
2. Raise and safely support hitch, transport frame and
front tongue.
3. Unpin rod end of tongue cylinder. Block, wire or other-
wise safely support cylinder so when rod end is fully
extended it does not contact anything.
4. Cycle cylinder completely in and out at least three
times to purge air from cylinder and hoses.
5. Fully extend cylinder and repin rod end.
6. Recheck tractor reservoir and fill to proper level.
Bleeding Transport Lift Cylinders
The transport-lift cylinders are rephasing cylinders and re-
quire a special procedure for bleeding air from the circuit.
Read and follow procedure carefully. Cylinders will not
function properly with air in the hydraulic circuit.
1. Check hydraulic fluid in tractor reservoir and fill to
proper level. Add fluid to system as needed. Trans-
port-lift-cylinder capacity is about 2 gallons (7.57 li-
ters).
2. Jack up and support hitch frame.
3. Remove 1/2-inch nylock nuts on spring side of cylin-
der-support brace. Unpin cylinders. Do not alter posi-
tion of jam nuts on center of support-brace bolts.
4. Turn cylinders to a position where rod ends are higher
than base ends. Support cylinders in a safe location.
5. Start tractor and run engine at idle speed. With rod
ends higher than base ends, hydraulically extend cyl-
inders. After cylinder rods are fully extended, continue
to hold control lever for one minute before hydraulical-
ly retracting cylinders.