Great Plains 3N-4025P Operator Manual - Manual (Page 149)

Great Plains Manufacturing, Inc. Table of Contents Index Maintenance and Lubrication 145
2014-01-29 Table of Contents Index 196-538M
Bleeding Hydraulics
To function properly, the hydraulics must be free of air. If
hydraulics have not been bled, they will operate with
jerky, uneven motions and could cause wings to drop
rapidly during folding or unfolding.
Crushing Hazard:
You may be severely injured or killed by being crushed from a
falling implement. Always have transport locks in place and
frame sufficiently blocked up when working on implement.
Bleed only at a
• JIC (Joint Industry Conference, 37
° flare) or
• NPT (National Pipe Thread, tapered thread) fittings, and
never at
• ORB (O-Ring Boss) or
• QD (Quick Disconnect) fittings.
Machine Damage Risk: JIC fittings do not require high
torque. JIC and O-ring fittings do not require sealant. Always
use liquid pipe sealant when adding or replacing (NPT)
pipe-thread fittings. To avoid cracking hydraulic fittings from
over tightening, and to keep tape fragments from clogging
filters, do not use plastic sealant tape.
Bleeding Lift Hydraulics
The lift system is equipped with rephasing hydraulic
cylinders that require a special procedure for bleeding air
from the system. Follow the procedure carefully.
1. Check hydraulic fluid level in tractor reservoir and fill
to proper level. Add fluid to system as needed while
cycling new cylinders.
2. Lower drill to ground.
Refer to Figure 198
3.
With frame blocked and supported, unpin rod ends
of wheel cylinders. Pivot cylinders up and wire or
otherwise safely support rod ends higher than base
ends. You may need to remove the cylinders from
the rockshaft so you can orient them with rod ends
higher than base ends.
4. With the tractor engine at idle speed, energize the lift
hydraulics. When the wheel cylinders on wings have
extended completely, hold the remote lever on for
one minute. Check all hydraulic hoses, cylinders and
fittings for leaks.
5. Retract the cylinder rods. Extend the rods again and
hold the remote lever on for one more minute.
Repeat this step two more times.
6. Again, check all hydraulic hoses, cylinders and
fittings for leaks. Recheck the tractor hydraulic
reservoir. Fill to the proper level.
7. Re-pin all cylinders.
During initial implement setup (which may have been
done by your dealer) or if you replace a hydraulic
component, complete the following procedures.
High Pressure Fluid Hazard: Escaping fluid under pressure
can penetrate skin, causing serious injury. Use a piece of
paper or cardboard, NOT BODY PARTS, to check for leaks.
Wear protective gloves and safety glasses or goggles when
working with hydraulic systems. If an accident occurs, seek
immediate medical attention from a physician familiar with
this type of injury.
.epsi
45%
Figure 198
Lift Cylinder Supported
16238