Stairmaster 4000 PT series, Owner'S Manual

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Page 43
MECHANICAL TROUBLESHOOTING
5. Remove the drive and step chains. Check the condition of the chains
by flexing each link up and down. Each link should move freely. Re-
place the chain if any stiff or inflexible links are found or if the chain is
rusty, corroded, or otherwise damaged. Do not reinstall the chains.
6. Spin the transmission drive sprocket input 1 complete revolution. The
transmission pulley output should turn 19 revolutions. Replace the
transmission if any clicking or grinding noises are heard during
rotation or the drive ratio is not 19 to 1.
7. Check the pedal arm and leveling arm shafts by removing both the
right and left pedal and leveling arms. Inspect the shafts and the
bushings for signs of wear and corrosion. Replace the bushing(s) if
worn.
8. Remove the pedals. Clean any corrosion off the pedal shaft with an
oil-dampened rag. Apply a thin coat of multi-purpose grease to the
shaft. If the noise persists, go to step 10. Check the step chain connec
tion point. Clean and grease the master link and bushing. Replace
damaged parts.
9. Check the drive hub assembly.
• Check the condition of the drive sprocket teeth. The teeth should
not be unevenly worn. Replace the worn sprocket(s).
• The drive sprockets work independently of one another. Each
sprocket should turn freely in one direction and lock when turned
in the other direction. Replace an inoperable drive sprocket.
• Remove the drive shaft. Inspect the bearings in the drive hub.
Replace the drive hub assembly if the shaft does not spin freely
or if there is excessive radial play at the shaft. Be careful not to
get dirt into the hub.
• Inspect the ends of the drive shaft (at the sprocket attachment
points) for signs of wear or scoring. Replace the shaft if it is
excessively worn.