TECHNOLOGY STORIES BIKE INFO, GEOMETRY ... - Vintage Trek

120
Fuel Pivot Service
Prepare the bike
1. Clamp the frame upright in a workstand by its seatpost
with the head tube vertical.
Removing the rear swingarm
1. Remove the rear wheel and right crankarm.
Disconnect the rear brake and rear derailleur cable.
2. If possible, open
the front derailleur cage
and remove the chain.
Otherwise, remove the
rear derailleur.
3. Identify the seat
stay pivot bolt (Fig. 32).
The bolt has a high
polish, while the axle
is anodized aluminum.
While holding the axle
with a 5mm allen
wrench, use another
5mm allen wrench to
loosen the bolt 4 to 5
turns. Tap the bolt head
to partially drive the axle
out of the assembly. Once
loose, you can probably
pull the axle (Fig. 33) out
with your fingers. As you
remove the axle, be careful not to let
the swingarm swing down and hit
the frame.
4. Remove the main pivot bolt
and axle, using the same technique
as with the seat stay pivot axle.
5. Ease the swingarm out of the
rocker bushings and off the main
pivot bushings. While pulling the
swingarm rearward, it may help to
wiggle the swingarm slightly from side to
side.
Removing the shock
1. If the swingarm is attached,
support the swingarm (especially
if the rear wheel is in the frame)
so that it doesn’t hit the frame
while removing the shock.
2. Hold the upper shock bolt
with a 5mm allen wrench while
loosening the nut with a 10mm
end wrench. Remove the nut, and
slide the bolt out. If the bolt has
Seat stay and rocker
pivot axle and bolts (identical)
Main pivot axle and bolt
Fig. 33
Upper shock mount
bolt (shorter)
Fig. 32
Lower
shock
mount bolt
(longer)
Fig. 34
been loose, its possible that it has cut threads in the aluminum
swingarm shock mount. In this case, you may need to
“unthread” the bolt from the frame.
3. Hold the lower shock bolt with a 5mm allen wrench
while loosening the nut with a 10mm end wrench. Remove
the nut, and slide the bolt out. Be careful not to drop the
shock as you remove the bolt.
2002 Trek Technical Manual
Removing the main pivot bushings
1. Remove the main pivot
bushing from the frame. This
part is held in place with
Loktite, so you will probably
need to lightly tap it with a
hammer to drive it out of
the frame (Fig. 35). A socket
on an extension makes a
good drift punch. The socket
should contact the metal portion
of the bushing, barely fitting
inside the swingarm and
pivot lug.
Do not use heat to loosen
the Loktite, as heat may damage
the frame or paint.
2. Remove the main pivot
bushing “top hats” (Fig. 36) from
the swingarm. These are also
installed with Loktite, so again
tap them out with hammer using
a properly sized socket. Avoid
damage to the swingarm by properly
supporting it as you drive out
the bushings.
Removing the rocker
1. Loosen the rocker pivot
axle, but don’t remove it yet.
2. Loosen each of the six
rocker bridge bolts holding
together the side plates of the
rocker (Fig. 37). To allow the
rocker to freely pass around the
seat tube, loosen each bolt 4 to
5 turns.
3. Remove the pivot axle,
and careful slide the rocker off
the frame.
4. Remove the rocker bridge
bolts and bridges (Fig. 38).
Rocker
pivot
axle
Fig. 35
Fig. 36
Rocker
clamp
bolts
Fig. 37
Inspecting the parts
1. Inspect the pivot bushings
in the upper end of the swingarm
as well as the rocker pivot
lug (Fig. 39). If they are in good
shape, they will be a light color
(Fig. 40) with no deformation,
Fig. 38
cracks, or chips.
If the bushings are damaged or worn, remove them.
These bushings are installed dry, so you should be able
to simply push them out. Do not use a screwdriver or
other sharp tool, instead try something blunt like an allen
wrench. If you use a sharp tool, you may cut or gouge the
bearing surface, and this damage would require replacement
of the bushing.