MBW AR57 - Manual (Page 12)

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10. Use a blind hole bearing puller to remove the two
needle bearings (#11 and #12) from the cover.
Breather Removal
Refer to Gearbox Assembly, page 14.
1. Remove the socket pipe plug (#29) from the top of the
breather assembly.
2. Remove spring (#19), washer (#28), and valve (#18).
Lower Unit Disassembly
The lower system can be separated from the drive unit
(engine, gearbox, and handle) without going thought the
complete disassembly procedure. If the lower unit has not
been separated, see Gearbox Removal, page 7.
Refer to Lower Unit Assembly, page 16.
Guide Tube and Bellows
1. Drain the oil from the system. Refer to Changing
Percussion System Oil, page 6.
2. Remove the six hex head cap screws (#21) and
lockwashers (#22) securing the spring box (#14) to
the bellows mount (#8) and guide tube (#9).
3. Remove the guide tube, bellows, and bellows
clamps.
4. Remove the retaining ring (#10) from the guide tube.
5. Remove the slide bearings (#5) from the guide tube.
Carefully drive the bearings out from the opposite
end of the tube. Be careful not to scratch or gouge
the inner guide tube walls.
6. Remove the six hex head cap screws (#23) and
lockwashers (#24) securing the shoe (#13). Remove
the shoe.
Springbox
WARNING
Working with compressed springs. Failure to
follow the next set of steps very carefully could
result in serious injury or death.
1. Flip the springbox assembly upside down.
2. Insert the springbox tool (MBW #20260) rods into the
springbox assembly as shown in Figure 4.
3. Make sure the rods are 180° apart.
4. Place the washers over the rods and run the nuts
down so the washers are snug against the cover (#3).
5. Remove the flat head socket screws (#20) holding
the cover to the springbox.
6. While holding the bottom of the rods from turning,
slowly and evenly back off the nuts on the cover side.
7. After the tension is removed from the cover, the
springbox tools and the cover can be removed.
8. Remove the o-ring (#6) from the cover and discard.
9. The lower springs (#1 and #2) can be removed from
the springbox (#21).
10. Place a drift pin or steel rod through the piston hole in
the ram head (#4). Use this to hold the ram head
from turning while removing the hex nut (#7). Discard
the hex nut
11. Remove the washers spring separtor (#17), and
upper springs (#1 and #2).
Gearbox Assembly
Make sure all bearings are pressed on square and are
seated properly. All shafts and housings should be lightly
oiled prior to pressing any bearings.
Refer to Gearbox Assembly, page 14.
Crank Gear Assembly
1. Press the bearing (#5) into the connecting rod (#8)
and secure with an internal retaining ring (#13).
2. Press the connecting rod assembly onto the crank
gear (#10) and secure with an external retaining ring
(#14).
3. Slip a retaining ring onto the crank gear.
4. Press a bearing (#4) onto the crank gear. Secure
with a retaining ring (#1).
5. Press the needle bearings (#11 and #12) into the
cover (#23). The bearing must be pressed in with
the numbers and letters facing outward.
Figure 4.
635,1*%2;
722/6