24 Owner Service
MAN0390 (Rev. 4/6/2007)
ADJUSTING SLIP CLUTCH
The slip clutch is designed to slip so that the gearbox
and driveline are protected if the cutter strikes an
obstruction. A new slip clutch or one that has been in
storage over the winter may seize. Before operating
the cutter, make sure it will slip by performing the fol-
lowing operation:
1. Turn off tractor engine and remove key. Remove
driveline from tractor PTO. Loosen six 10 mm cap
screws (6) to remove all tension from Belleville
spring plate (5).
2. Hold clutch hub (3) solid and turn shaft to make
sure clutch slips.
3. If clutch does not slip freely, disassemble and clean
the thrust plate faces (4), flange yoke (1), and
clutch hub (3).
4. Reassemble clutch. Tighten Belleville spring (5)
until it is against the thrust plate (4) of the clutch,
and then back off each of the six nuts by two full
revolutions. The gap between Belleville spring and
thrust plate should be 1/8" as shown in Figure 15.
5. If a clutch continues to slip when the spring is
compressed to 1/8", check friction discs (2) for
excessive wear. Discs are 1/8" when new. Replace
discs after 1/16" wear. Minimum disc thickness is
1/16".
RUBBER DISK REPLACEMENT
The flexible coupler side drive is designed to flex when
striking heavy objects or during start-up to protect gear-
boxes. The rubber disks will wear out over time and
require replacement much like slip clutch disks. To
maximize rubber disk life, lower tractor engine speed to
an idle when engaging the PTO and avoid striking the
ground with cutter blades.
Periodically inspect the disks for signs of cracking. A
disk may run for some time after a crack starts but this
is the first sign that disk replacement is required in the
future.
To replace the disks, remove hardware items (6, 7, 8,
and 9). Remove sleeves (7) from old disk and install in
new disk. Reassemble and torque bolts to 85 lbs-ft.
See Figure 16. Take special care not to rotate gearbox
shaft and throw blades out of time. If rubber disks have
failed and blades are hitting, you will need to re-time
the blades per instructions on page 34.
Figure 16. Flexible Coupler
1. Complete drive
2. Inner connector yoke
3. Outer connector yoke
1-3/4 20-spline
4. Outer connector yoke
1-3/4 6-spline
5. Rubber disc
6. Shaped washer
7. Bushing, .63 ID
8. Hex head cap screw
9. M16 x 2.0 Lock nut
10. Grease fitting
11. 3/8 NC x 3/4 Square head set screw
(Rev. 2/6/2009)
