Great Plains PD8070 Operator Manual - Manual (Page 69)

Great Plains Manufacturing, Inc. Table of Contents Index Maintenance and Lubrication 65
2014-07-23 Table of Contents Index 401-479M
Bleeding Hydraulics
High Pressure Fluid Hazard:
Escaping fluid under pressure can penetrate the skin, causing
serious injury. Avoid the hazard by relieving pressure before
disconnecting hydraulic lines. Use a piece of paper or
cardboard, NOT BODY PARTS, to check for suspected 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.
Bleed at a fitting of type:
JIC (Joint Industry Conference, 37 degree flare) or
NPT (National Pipe Thread) fitting.
Avoid bleeding at fittings of type:
ORB (O-Ring Boss) or
Never bleed at a fitting of type:
QD (Quick Disconnect) fitting.
JIC fittings do not require high torque. JIC and ORB fittings do
not require sealant.
Bleeding Lift Hydraulics
Refer to Figure 72
Normally the lift hydraulics are bled at the factory before
shipping, and bleeding should not be required other than
to raise fully and hold lever on for one minute or until all
cylinders extend fully.
If it is necessary to further bleed lift system, follow these
steps.
1. Consult lift circuit hydraulic diagram on page 98
(repeated at right in smaller scale)
2. Check that tractor hydraulic reservoir is full. Set
hydraulics for low flow rate.
3. Lower planter.
4. Loosen the JIC fittings at the rod ends (bottom) of
the three left lift cylinders. Leave the right
undisturbed.
5. Extend the lift circuit until fluid appears at each the
loosened fittings. As fluid appears, set control lever
to neutral and secure each fitting.
6. Retract the circuit. Set control lever to neutral.
7. Extend the lift circuit until both cylinders are fully
extended.
8. Loosen the JIC fitting at the base (top) ends of the
three right lift cylinders. Leave the left undisturbed.
9. Retract the circuit until fluid appears at each
loosened fitting. As it appears, set control lever to
neutral and secure each fitting.
10. Set circuit control to neutral and secure fitting.
11. Unless it is suspected that a large amount of air is in
the line between the cylinders, rely on the normal
re-phasing operation to purge it. Otherwise...
12. Loosen the JIC fitting at the base (top) end of the left
cylinder .
13. Retract lift circuit until fluid appears.
14. Set circuit to neutral and secure fitting.
15. Extend and retract circuit several times.
Figure 72
Bleeding Lift System
25463
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2
3
1
1
2
2
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2
3