Rebuilding the Jab Linkage Pivots

Remove the Jab derailleur from the bike. There is no need to break the chain. You can remove the upper chain pulley and lower cage spacer, and the chain will come out of the derailleur.

Clean all dirt off the links, pivots, and surrounding areas.

Set the cage lock with a tool as shown.

Back the 2 limit screws out so the linkage can move through its full range. This will make disassembly and re-assembly easier.

Remove the four M3 nuts from the link pivots.

Remove four M3 screws from from the link pivots.

Note: Many torque screwdrivers are not intended to be used in reverse. To remove the nuts, we recommend to use a regular screwdriver.

For the rebuild, we strongly recommend to use new plastic bushings and M3 nuts. This will ensure the pivots run smoothly and remain tight. 

If you re-use the bushings and nuts, make sure to clean them completely with degreaser and isopropyl alcohol so they are thoroughly cleaned.

Do not use bushings with fine grit in them.

Do not use nuts that have damaged locking tabs, and do not use nuts that have a nylon threadlocking insert (aka nyloc nuts).  The nut locking feature must be a metal clip. Alternatively, it could also be a distorted thread lock nut. This is important for the reliability of the pivots in use.

After the bushings are in the links, check that they fit to the derailleur by sliding them over the mating derailleur areas. There should be no friction when they rotate.

If they fit too snug, squeeze the bushings as shown with a pliers with parallel jaws (such as one from Knipex). This will compress the bushing just enough to fit over the mating parts with no friction.

After you verify the bushings all fit properly, coat the inside diameters of the bushing and the exposed aluminum holes in the links completely with grease.

It is OK to apply too much because it will get cleaned off later. The purpose of the grease is to prevent water and grit from entering the bushing, so it is better to have too much than too little.

Make sure the 2 linkage springs are still nested, and hooked completely though the holes on the derailleur.

If they are not hooked completely, the following steps will help re-install them. Note: The springs do not take much force to install if they are held at the right orientation during the installation.

Nest the 2 springs, with hooks aligned.

Install the spring to the mounting bracket by holding it in the orientation shown. Then push the hooks through the hole.

The hooks should go all the way through the hole, ending as shown.

Install the spring to the clutch housing by holding it in the orientation shown. Then push the hooks through the hole. 

The hooks should go all the way through the hole, ending as shown.

Make sure all 4 hooks are all the way though the holes, or it will not be possible to install the M3 screws.

Place the inner link over the hole on the mounting bracket at shown.

Important:

The triangular protrusion shape on the inner link should be near the hole as shown. This shape is for the limit screw.

Place the outer link over the mounting bracket and clutch housing.

For the mounting bracket hole, slide the M3 x 40mm long screw (with top cap and bushing) through the hole from the top, and seat it all the way down inside the greased bushing hole.

For the clutch housing hole, slide the M3 x 40mm long screw (with top cap and bushing) through the hole from the top, and seat it all the way down inside the greased bushing hole.

Slide a metal bushings over the ends of the two M3 screws, and into the greased bushing holes. Press them in all the way in with a pick.

Important:

Use isopropyl alcohol and a clean rag. Clean the exposed threads and bushings completely to remove all grease and oil. This is critical for proper threadlocking compound curing and for reliability of the pivots when the derailleur is in use.

Saturate the rag with IPA, then press it over the threads and rotate back and forth until you are certain all grease is removed. Do this for all 4 threads.

Important:

Use a strong threadlocking compound for the nuts. We recommend Red Loctite 277, or 263. This will provide the most reliable retention of the nuts.

Also, we recommend to follow the torque setting of 8 in-lb (0.9 Nm) for the most reliable retention of the nuts. Tighter is not better.

Apply the threadlocking compound to all 4 screw threads in the amount shown here.

Install the 4 nuts with your fingers.

Then tighten the nuts using a torque screw driver to ensure the correct torque is achieved. 8 in-lb (0.9 Nm).

Using a rag, wipe off all excess threadlocking compound from the 4 locations.

Make sure no threadlocking compound remains between the metal bushing and the aluminum link or it could lock the link in place.

It is OK to have a bit of threadlocking compound visible under the nut.

Now is a good opportunity to re-apply threadlocking compound to the 2 limit screws so they stay in place, but allow adjustment.

You can use boiled linseed oil (a technique used by wheelbuilders) or you can use Vibra-Tite VC-3. The idea is to use a gummy material that will allow for a few adjustments without allowing vibration to cause the screw to change its adjustment.

Boiled linseed oil will take about a day to change from a liquid to a gummy consistency. If you are not in a rush and want the best result with boiled linseed oil, you can coat the hole or screw, let it get firm over night, then install the screws. Vibra-Tite VC-3 will be gummy very soon after application.

You can now re-install the derailleur.

Installation and adjustment instructions are here.

Done!