REAR DRUM ASSEMBLY
The rear drum assembly consists of 2
drum covers, 2 flywheel cross frame/axle units and one set of bearings. The
following is a description of how the unit assembles/disassembles and failures
associated with each component. Remove the foot-tubes, main covers and flywheel
belt as previously outlined to access this area.
DRUM COVER AND CROSS FRAME ASSEMBLY
- Check for problems within the rear drum assembly. Rotate the assembly checking for noise or unsmooth rotation which may indicate worn bearings. If there is a presence of lateral fluctuation during rotation this may cause belt misalignment and lead to noise problems. This can be an indication that the cross frames are distorted.
- Check for play within the assembled units; Grab hold of the right drum and attempt to move in and out. If there is any lateral movement this could indicate that the securing bolt is loose. However, re-tightening this may only be a partial solution as wear may have already occurred on the cross frame axle joint. The cross frames often need to be replaced in this situation. Finally remove cap from the center of the right-hand side drum cover.
- Separating drum cover and cross frame assemblies A standard (Shimano style) crank puller and adaptor will be required. Remove the securing bolt and replace it with the adaptor until approximately 5mm is still exposed above the internal face of the right side cross frame.
- Screw the crank puller into the internal thread of the right side cross frame until firm.
- Use a wrench to turn the top half of the extractor tool until the 2 units are separated. Remove extractor tool and adaptor.
- If required, remove the left side assembly by the following method: Remove the circlip and washer located on the end of the axle (projecting through the right side) and then pull the left side unit away. If the unit cannot be pulled off, tap the end of the axle gently with a soft faced hammer until removed.
The adaptor can be made by cutting a
piece of 8 x 1.25 mm threaded steel rod to 25mm in length and cutting a slot
into so that it can be turned using a slot–head screwdriver.
