Great Plains NTA3007HD Operator Manual - Manual (Page 135)

Maintenance and Lubrication 131
04/04/2011 166-207M
Marker Maintenance
Review “Marker Safety Information” on page 61 before
performing maintenance on markers.
See also:
“Marker Operation (Option)” on page 61,
“Marker Adjustments” on page 99, and
“Initial Marker Setup” on page 163.
Marker Shear Bolt
The marker arm is attached to marker body with a shear
bolt
, which is intended to fail if the marker strikes an
obstruction, allowing the marker to swing back around a
second bolt
.
If the shear bolt breaks, replace it with an equivalent
7 ⁄
16
-14x2in Grade 5 bolt (Great Plains part 802-589C).
If that size is not available in your local market, substitute
an M10x1.5 Class 8.8 metric bolt and nut.
If your conditions result in frequent shears, the marker
shear base has storage holes for spare bolts.
Note: Replacing the bolt with a lower grade, or smaller
size, can result in nuisance shears.
Replacing the bolt with a higher grade can result in marker
damage.
Marker Hydraulic Bleeding
1. Review warnings, bleeding notes and system infor-
mation on page 112.
Refer to Figure 151
2.
With markers unfolded in field position, crack hydrau-
lic-hose JIC fittings at base
and rod ends of
each marker cylinder.
3. With tractor at idle speed, activate tractor hydraulic
valve forward until oil appears at a fitting. When oil
begins to seep out around a fitting, tighten that fit-
ting. Reverse the tractor hydraulic valve until oil
appears at opposite hose fitting. Tighten that fitting.
4. If you have dual markers, activate tractor hydraulic
valve forward again until oil seeps out around a fitting
on the other marker cylinder. Tighten that fitting.
Reverse tractor hydraulic valve until oil seeps out
around remaining hose fitting and tighten it.
5. Fold and unfold markers slowly to work out all air.
Note: Use caution when folding and unfolding markers for
the first time, checking for pinching and kinking of
hoses.
Null4:
Figure 150
Marker Shear Bolt
23204
1
2
You may be injured if hit by a folding or unfolding marker.
Markers may fall quickly and unexpectedly if the hydraulics
fail. Never allow anyone near the drill when folding or unfold-
ing markers.
1
2
Null4:
Figure 151
Marker Bleed Points
29489
1
2
1
2
1 2