Dura-Ace levers are the most serviceable of all the 9-speed STI levers. They are readily dismantled and can be separated down to the most basic components. All the more pity then that spare parts are not available.
These pages are specific to Dura-Ace 9-speed STI levers.
They show the strip-down and re-assembly of the ST-7700
family of levers, specifically, ST-7700-C left & right
and ST-7703 triple levers.
Earlier 7700 range levers are very similar and differ in only
minor detail, mainly related to the Flightdeck interface.
9-speed Dura-Ace was introduced in 1997 and continued until superseded by 10-speed in 2004. The triple option was introduced in 2002.
The construction of levers is very similar and procedures and photographs have been combined here. Where there are important differences, these have been highlighted. Note that levers are handed and most parts are not interchangeable left to right.
Remove the name plate retaining screw and name plate.
Remove the dust cover retaining screw and the dust cover. Note position and routing of Flightdeck cable under dust cover.
Remove the front cover retaining screw.
The front cover extends back over the top of the shift mechanism
and engages in the adapter plate.
Unhook the front cover from the adapter plate and carefully ease it forwards. The front cover houses the outer lever return spring so allow the cover to rotate to release the spring tension. Recover the spring.
|Between the cover and the shifter spindle there is a square plastic bush and a steel washer. They may remain on the spindle or come away with the front cover.|
Mount the lever in a vice by an M4 bolt threaded into the front
of the spindle.
Using Shimano service tool TL-ST01 (p/n Y-130 03000) and a 5mm hex wrench, unscrew the adapter plate retaining nut. Avoid putting too much load on the spindle while loosening the retaining nut by holding the adapter plate with a rod (e.g. screw driver) inserted through the brake lever pivot.
|Remove the retaining nut, the serrated washer, the adapter plate and plastic dust cover.|
|Remove the screw retaining the inner lever and the outer cover plate. If the screw is tight, it may be better to clamp the lever itself in the vice between soft jaws. Clamp the lower, hand grip part, of the lever only, not the shift mechanism housing which may be crushed.|
Left hand lever:
there is one outer plate and the release plate spring runs between the outer plate and release plate. One end engages in the adapter, the other in the release plate.
Right hand lever:
there are two outer plates and the release plate spring runs between the outermost plate and the adapter.
|Remove the inner lever, return spring and outer pawl cover plate.|
Remove release plate and bush.
Remove outer ratchet pawl and spring.
|Remove lever from vice, and working from the front, remove lock ring, bearing cone and ball cage. You'll need a thin 9mm across flats spanner such as the cone adjusting wrench supplied with retail Dura-ace levers.|
Slide shifter mechanism, with FlightDeck cable,
from lever body.
Recover inner ball cage.
Mount the shifter mechanism in vice
(4mm bolt threaded into spindle again).
Ease the ratchet drum (white nylon) away from the FlightDeck sensor (grey plastic) to disengage tabs. The objective being to prevent the sensor turning as the tension spring is released.
Slide the shifter mechanism off the spindle.
The mechanism is under tension by the spring housed in the
ratchet drum which engages in the splined bush below the drum.
It remains tensioned until either
the pawl cage comes off the spindle or the
spring disengages from the bush.
Remove the pawl cage from the ratchet drum and disengage the bush below the drum from the spring.
Slide the FlightDeck sensor from the spindle. Don't try to rotate the sensor through a full circle as this may damage the contacts.