Replacing Final Drive Seals

[ringadingh]

I went for a short ride on Saturday, and when we returned home I noticed that my rear wheel was covered in gear oil. Since it was not dripping out at the driveshaft boot. I figured it was one of the other seals in the final drive rather than the more common pinion shaft seal. I removed the wheel and final drive unit and after checking determined that it was the inner ring gear seal, the hardest one to replace. I checked in my manual to see what I was up against and decide to give it a shot.
I started by removing the lock collar that holds the pinion gear in the case and then pulled it out. I replaced the pinion shaft seal since I had it apart already with a standard seal from the bearing supplier, its a standard 40x52x7 nitrile seal an $8.00 part.


Then I removed the bolts that hold the ring gear assembly together and pulled the ring gear out of the case as well.


Once the case was empty you can see the bearing and seal in the bottom of the hole, in the last picture. I removed them both and replaced the seal with a new one. It was available at my local bearing supplier for $7.00 its a standard 35x47x7 nitrile seal. If the inner ring gear bearing needs to be replaced that will be a dealer item, since it is an automotive type p/n and isn't available to industrial suppliers.Then it was just a matter of putting it back together again. Its not that bad a job once youve done it, but it was quite intimidating while I read up on it. As long as you pu it back together with the shims in the same way it came apart it should be fine. The pinion gear and shaft comes out all together so there is no preloading or shimming required, its the same for the ring gear assembly, as long as you dont dissasemble any further it fine.
I mounted the final drive and wheel back on the bike and filled it with oil. After about a 25 mile ride around town and on the highway everything looks and feels ok so far. I'll keep my eye on it for a bit and see if it stays dry. There is only one more seal that I havn't replaced yet, and its the large outer ring gear seal, it looks good so far, but when the time comes it looks like an easy one to replace, you could probably do it on the bike if you had to. I was told that it is also a dealer item, just like the inner bearing is