Great Plains YP4025A Operator Manual - Manual (Page 114)

110 YP4025A Table of Contents Index Great Plains Manufacturing, Inc.
401-627M Table of Contents Index 2013-04-24
Marker Maintenance
Marker Cylinder Bleeding
Refer to Figure 134
1.
Begin with planter unfolded and lowered, and with
both marker sides extended. See “Unusual Marker
Operations” on page 55.
2. Note the position of the gravity pin lock (above and
latched on rod-end pin when folded, hanging down
when unfolded).
3. Un-pin the rod end of the marker cylinders, and
orient the cylinders so that the rods may extend
without striking marker components.
4. Loosen the JIC fitting at the base end of one
marker cylinder.
5. Extend the circuit until fluid appears at the loosened
fittings. It may be necessary to extend-retract-extend
to cycle the sequence valve to that marker. Set
circuit to Neutral. Secure fittings.
6. Loosen the JIC fitting at the rod end of that same
marker cylinder.
7. Retract the circuit until fluid appears at the loosened
fittings. Set circuit to Neutral. Secure fittings.
8. Repeat for the other side.
9. Re-orient gravity pin lock to position noted at step 2.
10. Re-pin marker rod ends.
Marker Shear Bolt Replacement
Refer to Figure 135
If a marker gets caught or hits an obstruction, it is
designed to fail a shear bolt at the fold, pivot on a pin,
and swing back.
The shear bolt is a hex head cap screw,
1 ⁄
2
-13 x 2
1 ⁄
2
in
Grade 5, Great Plains part number 802-130C, plus a
1 ⁄
2
-13 lock nut, Great Plains part number 803-019C.
Install a replacement shear bolt on the vertical faces on
the side opposite from the pivot bolt. Do not use a higher
grade bolt, or marker hang-ups may result in machine
damage. Do not use a lower grade bolt, or you may
experience nuisance shears.
Marker Grease Seal Cap
If grease seal cap for marker-disk-hub bearings is
damaged or missing, disassemble and clean hub.
Repack with grease and install new seal or grease cap.
Figure 134
Marker Bleed
26131
2
1
1
2
1
2
Figure 135
Marker Shear Bolt
29292