Great Plains 3PYP Operator Manual - Manual (Page 92)

88 3PYP Table of Contents Index Great Plains Manufacturing, Inc.
401-312M Table of Contents Index 2014-09-09
Marker Maintenance
Marker Shear Bolt Replacement
Refer to Figure 105
If a marker gets caught or hits an obstruction, it is
designed to fail a shear bolt
at the fold, pivot on a
second bolt , and swing back.
The shear bolt is a hex head cap screw,
7 ⁄
16
-14
×
2 inch
Grade 5, Great Plains part number 802-589C, plus a
7 ⁄
16
-14 lock nut, Great Plains part number 803-200C.
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.
Refer to Figure 106
If your planting frequently encounters shear hazards, you
can store 6 spare shear bolts/nuts per marker side, in
storage holes
at the fold point.
Marker Chain Length Adjustment
Great Plains suggests checking marker chain slack
every few years. If any maintenance or repairs cause the
chain to be disconnected, correct slack needs to be set
on reinstallation.
Perform any checks and adjustments with the marker
folded and tilted down into its cradle.
Refer to Figure 107
At the midpoint in the exposed chain, pull it toward the
front of the planter.
Measure the distance between that mid-point and the
nearest point on either of the two parallel tubes of the
marker intermediate arm. The target value is:
18 inches (46 cm).
If the slack is outside this range, remove the bolt and nut
at the lower end of the chain and adjust the length.
Figure 105
Marker Shear Bolt
25263
2
1
1
2
2
Figure 106
Marker Shear Bolt Storage
25264
3
1
3
A chain length too short or too long can result in marker
damage.
Figure 107
Marker Chain Slack
25266