Tracker Front Hub
To disassemble your hub, loosen the set screw on the adjustable side of your hub. If you can not pull the adjustable axle end from the hub axle by hand, thread in a 6mm bolt into the axle end and pull. If it still does not budge, insert an old quick release skewer or rod down the axle from the non-adjustable side so that the end of the rod butts up against the end of the screw. With a mallet, hit the end of the rod until the axle end dislodges from the axle. Next, push the axle through the hub shell and out the non-adjustable side. If the axle does not move freely, use a rod or socket approximately 17mm in diameter, butt it up against the axle, and pound it through the shell. The collar will fall out and the bearings will be exposed to you. Test the bearings to insure that they are running smoothly. If they are gritty, pull the seals on the bearings or remove the bearings from the shell and clean. Repack with fresh grease and replace seals. If they are still gritty, replace with new bearings.
The bearings are #6903 or 17mm I.D. 30mm O.D.
To reassemble your hub, first make sure that the press-in axle end (non-adjustable axle end) is fixed in the axle. You should not be able to separate it from the axle. If you can, re-lock-tite the axle end into the axle using RC 680 (green). Insert the axle into the hub shell, replace the hub collar making sure the inside step for the axle end faces outward. Now insert the adjustable axle end. Place the wheel on its side so that the press-in axle end is on your work bench. Hold onto the rim and press down. You can take a socket, place in on top of the collar, and tap on it to make sure that it is fully seated. Tighten the set screw and feel for play in the hub. If the hub is seated tightly you are ready to roll.