Great Plains YP2425A Operator Manual - Manual (Page 111)

Great Plains Manufacturing, Inc. Table of Contents Index Maintenance and Lubrication 107
2014-02-10 Table of Contents Index 401-626M
Marker Maintenance
Marker Bleeding
To fold properly, the marker hydraulics must be free of
air. If the markers fold in jerky, uneven motions.
Marker Cylinder Bleeding
Refer to Figure 138
1.
Begin with planter unfolded and lowered, and with
both marker sides extended. See “Unusual Marker
Operations” on page 38.
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 139
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
inch 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.
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 138
Marker Bleed
26131
2
1
1
2
1
2
Equipment Damage Risk:
Replacing shear bolt with a higher grade bolt can result in
marker damage. Replacing the shear bolt with a lower grade
can result in nuisance shears.
Figure 139
Marker Shear Bolt
29516
1
2
1
2