Stairmaster FreeClimber 4600 PT Owner's Manual page 67

5. Remove the drive chain.
6. Remove the sprocket and the other small parts from the left side of the
hub assembly (see Figure 21).
7. Slide the drive shaft to the right, out of the hub assembly. If you remove
the right-hand clutch sprocket from the drive shaft, do not confuse it
with the left-hand clutch sprocket.
8. Loosen and remove the two remaining bolts and nuts that hold the hub
assembly to the frame. Remove the hub assembly.
9. Inspect the drive shaft, the bushings, the thrust washers, and clutch
sprockets for excessive wear or pitting. Replace worn-out components.
10. To reinstall the hub assembly, carefully reverse the disassembly
procedures. Be sure that the right- and left-hand clutch sprockets are
positioned correctly; the wide shoulder of the sprocket should be facing
away from the hub on both sides.
11. Chain Tension. The drive shaft is mounted in an eccentric hub. Rotate
the hub so the marked hole is in the 12 o'clock position, lining up four
holes in the hub with the four holes in the frame. Use this hub position
when reinstalling the drive chain since the distance between the drive
and transmission shafts is at a minimum. The hub is in the proper
position when the drive chain has a total of 1 to 1-1/2" (2.5 to 4.0 cm) of
play at the slackest point. As the drive chain stretches with use,
increase the chain tension (and the distance between the two shafts)
by rotating the hub counterclockwise (see Figure 29). The distance
between the two shafts is greatest when the marked hole in the hub is
at the 8 o'clock position.
12. Reinstall the covers.
PARTS REMOVAL AND REPLACEMENT
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