Great Plains 1205NT Operator Manual - Manual (Page 21)

3/28/12 150-131M
19 Preparation and Setup
Bleeding Hydraulics
High Pressure Fluid Hazard:
Escaping fluid under pressure can have sufficient pres-
sure to penetrate the skin. Check all hydraulic lines
and fittings before applying pressure. Fluid escaping
from a very small hole can be almost invisible. Use pa-
per or cardboard, not body parts, and wear heavy
gloves to check for suspected leaks. If injured, seek
medical assistance from a doctor that is familiar with
this type of injury.
Check that tractor hydraulic reservoir is full.
The drill lifting system is equipped with rephasing
type hydraulic cylinders that require a special pro-
cedure for bleeding air from the hydraulic circuits.
Read and follow this procedure carefully. Rephas-
ing type cylinders will not function properly with air
in hydraulic circuit.
1. Check hydraulic fluid in tractor reservoir and
fill reservoir to proper level. Drill-system ca-
pacity is about 1 gallon. Add fluid to system as
needed. A low reservoir level may draw air
back into the system, causing jerky or uneven
cylinder movements.
2. With drill attached to tractor, jack drill up and
support frame at ends near gauge wheels.
3. With drill raised and supported, unpin cylin-
ders from gauge wheel arms and frame. Turn
cylinders "rod end up". Wire or otherwise
safely support rod ends higher than base
ends.
NOTE: In order to prevent trapped air pockets, rod
end must be higher than any other part of cylinder
during bleeding operation.
4. With tractor engine idling, engage tractor hy-
draulics to extend cylinder rods. When cylin-
der rods are completely extended, hold
remote lever on for one minute.
5. Retract cylinders. Extend cylinders again and
hold remote lever on for one more minute. Re-
peat this step two more times to completely
bleed system.