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Final Drive to Driveshaft Housing Seepage and Shimming

B

bobct

Member
Member
Changed out my rear tire yesterday and the way I do it I pull the final drive out.
I noticed I had some dried up seepage of final drive fluid at the driveshaft housing mating surface. Did a search and found there is an oring in the driveshaft housing that fails. Well my search in the microfiche showed the oring but brought up another question.
The microfiche shows a shim between the final drive and the driveshaft housing and lists numerous thicknesses from T=.15 to T=1.0. I'm assuming that T is thickness in mm, which is @ a .035" range.
I do not have a shim there and because the driveshaft housing and the final drive combined length make up the left side swing arm length I'm thinking the shim thickness is selected at the factory to make the swing arm lengths equal.
The rear axle comes out before loosening final drive but mounting final drive to wheel first with putting rear axle into final drive and left side of wheel then mount final drive to driveshaft housing loosely then finish axle assembly the tighten the final drive.

Has anyone looked into this and have a method for determining the right shim thickness? OR am I overthinking this up to 1mm possible change in left swingarm length?

If anyone has insight on replacing the oring that allows the leakage from between the final drive and driveshaft housing please post.
 
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Trying to figure out which oring fails causing the leak between the final drive housing and driveshaft housing. The final drive gear oil lubricates the splined drive shaft coupling I beleive, so is the culprit oring that fails the one forward of the drive shaft coupling, 92055C? If so it looks like with the final drive removed and the spring removed from the driveshaft coupling you remove the circlip from inside the drive shaft coupling then the coupling can be removed from the driveshaft? Leaving an oring inside the coupling and what I think is the culprit oring behind the coupling? Or is it the oring 92026 failure behind the circlip inside the coupling that causes the leakage. Thanks Brock Delp for posting the microfiche. If you need to look at a C10 microfiche or some of his postings on his site, do a search by his name adding "concours 1000" and you should find his site.
Driveshaft.gif

As far as the shim size width selection between the final drive housing and driveshaft housing. I think I would come up with some sort of jig to measure both swing arm lengths to the rear axle or from front axle to rear axle.
 
Pulling the final drive to change a tire seems like a lot of extra work, I often swap out my tires since I have 2 sets of wheels & tires & it only takes me 10 min to swap the rear out & that includes gathering the neededtools.
 
bobct said:
Trying to figure out which oring fails causing the leak between the final drive housing and driveshaft housing. The final drive gear oil lubricates the splined drive shaft coupling I beleive, so is the culprit oring that fails the one forward of the drive shaft coupling, 92055C? If so it looks like with the final drive removed and the spring removed from the driveshaft coupling you remove the circlip from inside the drive shaft coupling then the coupling can be removed from the driveshaft? Leaving an oring inside the coupling and what I think is the culprit oring behind the coupling? Or is it the oring 92026 failure behind the circlip inside the coupling that causes the leakage. Thanks Brock Delp for posting the microfiche. If you need to look at a C10 microfiche or some of his postings on his site, do a search by his name adding "concours 1000" and you should find his site.
Driveshaft.gif

As far as the shim size width selection between the final drive housing and driveshaft housing. I think I would come up with some sort of jig to measure both swing arm lengths to the rear axle or from front axle to rear axle.
Click to expand...
At the base of the drive shaft housing you will see O-ring #92055C and a sleeve/coupler #42034A.
I think this is the O-ring that leaks...

Ride safe, Ted
 
Thanks Ted, that seemed like the likely culprit. I have everything back together with a new tire. I will order up that oring and probably the other oring inside the coupler behind the circlip, just in case when I pull the coupler it gets damaged. I will also make sure I have a circlip removal tool with attachments that can get to that semi-buried circlip.
So I will keep an eye on the seepage and enjoy some riding on the new tire.

Zarticus, yes it is easier to change the wheel out without removing the final drive, especially with a stock wheel. I have a cutback rear fender and if I put the centerstand feet on 2x6 I can wrestle to get a 170/60 tire in and out, removing some air and working the chinese puzzle but I like to get a good look at the final drive hub splines. With this seepage present I wanted to see what was going on there too. Wait a minute, your ride, according to your sig line is a 2012 C14, how is the clearance (rear fender, final drive, brake rotor to frame, etc.) for removal of the rear wheel.

Ten minutes, including getting it up on the centerstand, getting tools, and changing out the wheel is near indy pit time in comparision, thata boy!!!
I have been thinking of spare rims too, I picked up one for the front a few years ago, that needs some cosmetic attention that I intend to work on to put my already bought front tire on, being able to change it out the day it is needed at your convenience must be nice.

Ref: Added "Seepage" and moved "Shimming" as secondary to Post title for future referencing
 
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Is that hard to replace the o-rings associated with the final drive case leaking?
 
it is not hard to change out the o-ring that is associated with the final drive leak it is the 92055C that Ted has identified.

If it has failed like mine did, it will drop out in pieces when the final drive housing is removed from the swing arm.

As far as the shim goes 92025/A~G, it is not for changing the length of the swing arm. It is for adjusting the pinion gear depth into the ring gear for correct tooth contact. It is selected at the factory and depends on the gear housing tolerances, as well as the pinion and ring gears. If you have issues with either gear, they are replaced as a set, and that is when you would need to change out that shim as well as the other 2, (ring shim and bearing preload shim).

It would be easier just to buy a final drive housing off ebay at that point, unless you like to work on gear sets at that level. Starting in section 10-8 in the full service manual shows you how to do that.

You wouldn't notice this shim (92025/A~G) unless you have pulled the pinion gear assemble out of the final drive housing.
 
Just replaced the o-ring in my 99, it has 77000 miles and is the 2nd time I have done it. The old seal split during removal and had a noticeable flat surface on the outside. The hardest part of the job is removing the snap ring to get the coupler off. You need a long reach set of pliers to get inside the coupler. I struggled for awhile then when I was looking through one of the many tool bags I have I found the set of hemostats I had ground to fit the snap ring. 2nd try and out it came. The first time I did it was about 8 years ago.
 
A common problem is a leak in that area.
I think it often comes from overfilling the rear end..

I simply lowered the oil level to just below the threads in the fill plug.
Never had the issue again..

NOTE: Many fill the rear end without a long/proper drain or rotate the gears while filling.
Oil is carried by the gears and later returns to the gear case.
ie; If you rotate the gears or do not drain properly and then fill to full, the result is an overfill that leaks because the oil level is to high.

Ride safe, Ted
 
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I never had to change out the o-ring on the opposite side of the coupler. The one that always went bad on mine is the o-ring that goes around part 42034, and that one is easy to do, no snap ring removal needed there.
 
mgoodrich, after reviewing the microfiche I stand corrected as I had that 92025 A-G Shim on the outside of Housing Bearing back, 41046, instead of on the inside which makes more sense for adjusting the pinion gear backlash, thank you for that as I was scratching my head why I didnt have a shim between the mating final drive to driveshaft housing surfaces.

As far as the seal that goes around 42034 coupling that causes the leak,
I could see the confusion where the proper oring that causes the seepage is, as both ends of the coupling use the same 92055C oring.
1​

​
​

92055C​
Ring - O
2​
 
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