MBW R422 - Manual (Page 11)

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Clutch Removal
Refer to Engine Assembly, page 21.
1. Remove the jam (#13) nut and slide the clutch off
engine crank.
2. Reinstall the clutch, making sure key remains in place
and aligned with keyway
3. Reinstall jam nut with medium strength thread locker
and tighten to 60 ft lbs (N•m).
Gearbox Removal
NOTE: It is necessary to remove the Handle and the
Engine to remove the Gearbox.
Refer to Gearbox and Lower Unit Assembly, page 18.
1. Drain the oil from the rammer following steps 1
through 3 under “Changing Percussion System Oil”
on page 6.
2. Replace the drain plug.
3. Remove the four hex head flange screws (#8) holding
the cover (#2) to the gearbox (#4).
CAUTION
NOTE: There may be oil in the gearbox. Tip the
unit back when removing the cover from the
gearbox.
4. Remove the cover (#2), the cover gasket (#3), and
the dowel pins (#1) from the gearbox.
5. Tip the unit forward and drain any oil into an oil pan.
6. Remove retaining ring (#7) from piston. Thread a 5/
16-18 screw into the piston connecting pin (#6) and
remove the pin. See Figure 1.
7. Remove the six hex head flange screws (page 16,
#21) holding the spring box guard (page 16, #12) to
the bottom bellows ring (page 16, #4).
8. Remove the gearbox assembly from the lower unit
assembly. See Figure 2.
Gearbox Disassembly
Refer to Gearbox Assembly, page 14.
Crank Gear Removal
1. Slip a retaining ring pliers through the slot opening in
the crank gear (#20) and remove the retaining ring
(#10) from the housing. The retaining ring will remain
between the crank gear and the bearing (#2).
2. Remove the SAE plug (#19) from the rear of the
gearbox. Use a 3/8 in. or (10mm) diameter steel rod
to press the crank gear out of the gearbox.
3. Remove the ball bearing (#2) from the crank gear
using a bearing puller. Remove the large retaining
ring (#10) from the back of the crank gear.
4. Remove the small retaining ring (#9) from the front of
the offset shaft on the crank gear and remove the
connecting rod (#5).
5. Remove the needle bearing (#6) from the gearbox
with a blind hole bearing puller tool (MBW #07552).
Pinion Removal
1. Remove the external retaining ring (#4) from the gear
end of the pinion (#21) on the inside of the gearbox.
If the retaining ring is pinched in its groove, tap the
pinion on the drum side. This will relieve the pressure
on the retaining ring.
2. Press out the pinion.
3. Pry out the oil seal (#11) and discard.
4. Remove the retaining rings (#10 & #18).
5. Use a bearing puller to remove the ball bearings (#2
& #22).
Figure 1
Figure 2