Replacing leaking final drive seals

[red2002]

The back wheel on my 2008 C14 was splattered with final drive lube, so it's time to replace a seal or two. (FYI, I did check to be sure that the drive was not overfilled; wish it had been.)

I have the service manual and it doesn't look all that daunting, but I do have a few questions for those of you who have already been through this process:

(1) Are the majority of leaks caused by failure of the "big" ring gear oil seal only, or is the "small" ring gear seal also a leaker? Guess I can replace both of them while I'm in there, but it if ain't broke.... The circumference of the big seal is wet with oil and it's obvious the it's leaking.

(2) Is it necessary to remove the pinion gear to extricate the ring gear/seal assembly? The manual shows its removal prior to replacing the big seal. Haven't looked inside the thing, yet, and the pictures aren't really clear.

(3) If both the ring and pinion are removed, can the existing shims be re-used, as-is, without messing up the backlash?

(4) Any tips or caveats?

Thanks,

Mike

[fmwhit]

Mike when I did the initial service on my 08 I over filled the final drive, not by much, just a little and I had the splatters that you are describing.  After a few hundred miles the splatters stopped and all has been fine since.  Just suggesting if you over filled the drive you may get some splattering till the levels go down.

Fred

[lather]

If you check the level on the cs and the front whyel on the ..ground it will be overfilled
and will slatter

[B.D.F.]

The majority of the leaks seem to be from the smaller seal behind the bearing.

It isn't all that big of a deal to replace both seals but you might want to buy a new bearing as well as the seals before beginning because you will have to press that bearing out to get to the seal behind it. Ignore Kawasaki's instructions to heat the entire assembly in a bath of hot oil until the large seal can be removed without any force (differential expansion- I guess it would work but who has a vat of 400+ degree oil laying around?)- you can pull the larger seal by very carefully driving a sheet metal screw into the seal body (a sheet rock screw works very well for this) and then prying the seal out by pulling on the screw head.

The ring and pinion are on the 'other side' of the ring gear carrier so the pinion can stay in place. The ring gear can stay in place on the carrier as I remember also- no need to re-pattern the gears to replace the seals.

It is a fairly straightforward job and not particularly tricky or difficult. As always when working on the 'innards', be careful not to nick or scratch the seal mating surfaces. Given sufficient tools and a reasonable work area, it is probably a 4 hour or so job for a professional mechanic.

Brian

The back wheel on my 2008 C14 was splattered with final drive lube, so it's time to replace a seal or two. (FYI, I did check to be sure that the drive was not overfilled; wish it had been.)

I have the service manual and it doesn't look all that daunting, but I do have a few questions for those of you who have already been through this process:

(1) Are the majority of leaks caused by failure of the "big" ring gear oil seal only, or is the "small" ring gear seal also a leaker? Guess I can replace both of them while I'm in there, but it if ain't broke.... The circumference of the big seal is wet with oil and it's obvious the it's leaking.

(2) Is it necessary to remove the pinion gear to extricate the ring gear/seal assembly? The manual shows its removal prior to replacing the big seal. Haven't looked inside the thing, yet, and the pictures aren't really clear.

(3) If both the ring and pinion are removed, can the existing shims be re-used, as-is, without messing up the backlash?

(4) Any tips or caveats?

Thanks,

Mike

[red2002]

Thanks for the replies!

fmwhit & lather: Know what you mean about the oil levels, but I really don't think it's due to overfilling. I've changed the final-drive oil several times and the leak just started a couple of thousand miles ago. When I first saw the splatter and puddle of oil under the bike, I cleaned the hub, drained the drive and carefully refilled. Still leaked. Really wish this were the cause.

B.D.F: Thanks for the tips; doesn't sound too bad. I'll replace both seals and the bearing. Glad the 400* vat of hot grease isn't necessary, as I'd planned to sneak it to the local McDonalds. Might've added a piquant aroma and bonus flavor to the fries.

There are 6" of snow on the ground here on the frozen tundra, so I'll not be riding anytime soon. This project should keep me occupied for a while.

Again, thanks.

Mike

[Conrad]

Thanks for the replies!

fmwhit & lather: Know what you mean about the oil levels, but I really don't think it's due to overfilling. I've changed the final-drive oil several times and the leak just started a couple of thousand miles ago. When I first saw the splatter and puddle of oil under the bike, I cleaned the hub, drained the drive and carefully refilled. Still leaked. Really wish this were the cause.

B.D.F: Thanks for the tips; doesn't sound too bad. I'll replace both seals and the bearing. Glad the 400* vat of hot grease isn't necessary, as I'd planned to sneak it to the local McDonalds. Might've added a piquant aroma and bonus flavor to the fries.
There are 6" of snow on the ground here on the frozen tundra, so I'll not be riding anytime soon. This project should keep me occupied for a while.

Again, thanks.

Mike

Not to mention the nice aroma that would emanate from the rear wheel once you've finished.

[elektradw]

Is it final drive gear oil that has leaked or spline grease? My C14 rear wheel was covered in spline grease after the first 500 miles. I too thought there was a leaking seal. Cleaned it up and kept riding and never happened again. I have also seen this happen when bearing grease is used on the final drive splines. Bering grease has the tendency to thin out with heat and be expelled by centrifugal force. Molybdenum disulfide grease is required and is much less prone to splatter out onto the rim. In addition, when filling the rear drive DO NOT rotate the wheel. The oil will coat and travel up the gears and you will definitely overfill the case.

[red2002]

Unfortunately, it is gear oil, the stinky stuff.

After I first noticed it, I pulled the wheel off and cleaned the inside of the hub and splines, hoping that it was the moly I'd used. After 100 miles or so, the black mess was slung all over the place, again. Also leaves a drop on the floor after the bike sits for a while.

I know what you mean about rotating the wheel while filling: the lube clings to the gear and shows a false low level. The bike didn't start leaking until ~20k miles and I've done 3 or 4 lube changes.

Wish it were just grease, but......

Thanks,

Mike