I messed up a tranny oil seal but don't know why

George_in_KG · 03-06-2008, 07:35 PM

Up until yesterday, I was feeling pretty good about my mechanical abilities. I tore the R bike down for a clutch replacement. The transmission input splines looked bad, so I went into the transmission and replaced the input shaft too. The transmission got all new oil seals after it was assembled. I was very careful when installing the oil seals. Wrapped the splines in electrical tape to protect the seal lip from the splines. The bike went back together and I had put about 200 miles on it over the last 10 days. Everything seemed great. Shifting was better than ever and I didn't have any parts left over.

I really got depressed when I noticed the puddle of gear oil under the rear tire yesterday.

The transmission output shaft seal had started leaking. Oil ran down the swing arm and out the boot at the final drive.

I just finished pulling the trans output seal and there is no obvious fault. There is no seal lip damage visible under the magnifying glass. It feels smooth.

Is there any secret for installing this particular oil seal? I don't see what I did wrong the first time.

Flatbutt1 · 03-07-2008, 05:15 AM

Not 100% sure which seal you're referring to BUT the one in the rear can be pushed in to deeply and result in a leak. IIRC

roger albert · 03-07-2008, 05:28 AM

Never have had a problem with that seal, so I don't know it well, but if you're sure it's not nicked, then it's usually a depth issue.

dee jones · 03-07-2008, 06:01 AM

This may sound stupid ,but are there any pranksters in the area? I've had guys dump oil around the area I've been working on. Probably not the case but thought I'd mention it.
As Roger mentioned its probably a depth issue. Good luck.

Kiriath · 03-07-2008, 10:31 AM

Quote:

Originally Posted by dee jones

This may sound stupid ,but are there any pranksters in the area? I've had guys dump oil around the area I've been working on. Probably not the case but thought I'd mention it.
As Roger mentioned its probably a depth issue. Good luck.

hahaha that would just be so mean!!

wswartzwel · 03-07-2008, 03:06 PM

Quote:

Originally Posted by Kiriath

hahaha that would just be so mean!!

If you knew Dee very well you would know he probably deserved it..

George_in_KG · 03-07-2008, 04:59 PM

Quote:

Originally Posted by dee jones

This may sound stupid ,but are there any pranksters in the area? I've had guys dump oil around the area I've been working on. Probably not the case but thought I'd mention it.
As Roger mentioned its probably a depth issue. Good luck.

I have a tough security team guarding my bikes at all times in the garage. No way someone could have snuck in and faked an oil spill. In some ways I wish that were the case. It would be a lot less work for me.

George_in_KG · 03-07-2008, 05:05 PM

Quote:

Originally Posted by Flatbutt1

Not 100% sure which seal you're referring to BUT the one in the rear can be pushed in to deeply and result in a leak. IIRC

It is the seal at the ass end of the transmission where the trans output shaft connects to the drive shaft.

I'm thinking that Roger's suggestion of seal insert depth must be the issue. I actually measured the insert depth of the original seal and was really careful when I installed the new seal. If there was a mistake, I must have been inserting it too deeply.

The service manager at my local dealer suggested packing the inside of the seal with grease to keep the lip from rolling up as the seal is pushed on the shaft. This doesn't seem likely, but I'll try it too.

Flatbutt1 · 03-07-2008, 05:29 PM

Yup thats what I was thinking. There was alot of discussion on that installation depth here some time ago.

George_in_KG · 04-06-2008, 08:12 PM

Thought I would follow up with a report on my output shaft seal saga. I removed the old (in service for 200 miles) seal and inspected it with a magnifying glass. Could not find any problem with it or the mating surfaces in the bike. It did not appear to be damaged during installation.

Installed a new seal but didn't seat it quite as deeply. This seems to have solved the problem. No oil leaks after two weeks and a few hundred miles. Looks like seating depth on this seal is more critical than it seems. Difference between correct position and placement that causes oil leak is < 1 mm, so be careful.

Thanks to all for the help.

roger albert · 04-06-2008, 09:18 PM

Wow, I've seen a few fail to seal due to wrong depth, but at a delta of less than a mm, that stinks. They're not usually _that_ critical, unless they're near a radius on the shaft.
Are you absolutely sure the leaker was in square? No matter, as you got it now. Good job.

Kiriath · 04-07-2008, 12:47 AM

Good to know, thanks for updating.