Great Plains PD8070 Operator Manual - Manual (Page 70)

66 PD8070 Table of Contents Index Great Plains Manufacturing, Inc.
401-479M Table of Contents Index 2014-07-23
Replacing Shear Pins and Bolts
Drive-Line Shear Pins
Refer to Figure 73
The cotter pins
that connect shafts to
transmission will shear when an excessive load is put
on the shafts.
Infrequent or improper lubrication causes binding of
moving parts within the planter. This binding will cause
cotter pins to shear, thus preventing breakage of planter
parts.
Check for binding by turning drive shaft with all seed
hoppers installed and seed meters engaged. If drive
shaft is hard to turn, disengage one seed-meter clutch at
a time to find the problem clutch.
Improper shaft alignment can also cause pins to shear.
See “Shaft Alignment” on page 67.
When shaft can be turned freely by hand, replace the
cotter pin
.
Machine Damage Risk:
Replace cotter pins with cotter pins of the same size. Do not
replace with other type pins. Refer to current Parts Manual for
replacement part number.
Marker Shear Bolt
Refer to Figure 74
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 (not visible in Figure), and swing back.
The shear bolt is a hex head cap screw,
5 ⁄
16
-18 × 1 1 ⁄
2
inch Grade 5, Great Plains part number
802-012C, plus a
5 ⁄
16
-18 lock nut, Great Plains part
number 803-011C.
Note: If an exact replacement is not immediately
available, temporarily substitute an
M8
×1.25 Class 8.8 bolt and nut.
Install a replacement shear bolt on the vertical face 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.
Figure 73
Transmission Shear Pins
25464
2
1
3
1
2
1 2
3
1
Figure 74
Marker Shear Bolt
25451
1
1