new shift shaft seal leaking

[Justin B.]

I didn't need any tools to install it, I slid it over the shaft and put the shaft in the recess and bolted it in

I went back and re-read your posts on this and I will be so bold as to say this is not the correct technique for installing this seal.  I doubt that it would wind up nearly deep enough.  You normally have to use a socket of the proper diameter (just smaller than the seal's bore) and use it as a drift to tap it to proper depth with a hammer.  I think right now pics are mandatory to see what is going on.

[Bob_Roller]

I checked how far in the seal is on my bike this morning, before leaving for work, and it looks like around 3/8ths of an inch from the the outer edge of the transmission to the seal.

[rob650]

ATTACHED PIC = the seal in the red square is the shift shaft seal I've replaced twice.  

The two pieces in the yellow square I just pulled out this morning, didn't realize they were removable parts.  The metal collar fits inside the plastic collar.  I couldn't find these parts on microfiche

Whats the right way to install the shaft seal?

[Bob_Roller]

The two parts in the yellow box look like a support/bearing assembly for the outer half of the shift shaft.

I went to REALOEM.com, and it just shows these two parts off to the side of the transmission .

I just used a socket slightly smaller than the seal, and tapped it into place about 3/8 ths of in inch in.

[Justin B.]

The bearing is necessary as a bore in the aluminum case wouldn't last long without some sort of bushing.  But, this does look a bit overengineered in the typical German manner!  

I think that what we can say for sure is your first seal was defective and I feel the root of your current problem is that the seal is not installed properly/to the correct depth.  I outlined the correct way to install a seal in the post at the top of this page.  It would also be OK to put just the slightest smear of silicone sealant on the outside edge of the seal where it contacts the bore.

[rob650]

reinstalled everything - the aluminum+plastic collar did take a tap with a socket to get it all the way seated, but the shaft seal goes all the way in with finger pressure.  Ill check later tonight for leaks..  If it does, my next step is to try the silicone sealant Justin mentioned.

[Justin B.]

It's been a long time since I've replaced this seal (I'm a cheap bastard and only replace stuff when it breaks) but something doesn't sound right about it seating all the way in with just finger pressure...

[rob650]

Still leaks, although at a slower rate than before.  I'll try the silicone sealant next

[Bob_Roller]

Being able push the seal in by hand is not right .

I'm wondering if at some point in the bikes past, the area where the seal is installed, was damaged during a seal removal, and then 'dressed' out with something like a wheel cylinder hone, so now the hole is slightly oversize.

When you use the silicone sealer, make sure the area is free from gear lube, and let the sealant sit for a day or two to fully cure before getting any oil on it.

I don't know if this would be a good idea or not, but would wrapping a few thicknesses of teflon tape around the seal before installation, might make it a tighter fit in the hole ?

[MrRiden]

Perhaps a measurement of the bore / shaft diameter [and seal] is in order. Alt sizing is available for the standard 26X16X7mm seal [ODxIDxwidth] http://www.epm.com/oil_metricpg4.htm You probably want a vinton, ETB or ETC style seal not a EV which has no spring.
rich

[nothing]

It sounds to me like you have the wrong seal. 4 speed transmissions and very early 5 speeds used a 24 mm OD seal, later 5 speeds used a 26 mm OD seal. Your bike should use the later larger seal. The proper seal will require some force to install in the transmission bore, it will not easily slip in with finger pressure.

The proper seal should be 26X16X7 (mm) - thicker will work as well, IIRC mine is 8 or 9 mm thick. They can be bought at any generic seal shop. I paid $1 for mine and it has not leaked a drop.

[Bob_Roller]

Do you have a receipt with a BMW part number on it ?

Can you see the size numbers on the seal itself ?

[rob650]

Mr. Riden and nothing :  seal measures 15 x 24 x 7, which is also stamped on the seal itself.

Bob_Roller, there is no part # on the seal, receipt says 23 11 1 006 124.

I did the silicone sealant yesterday and took the bike out for a ride today, seems to have done the job.  Not a drop has appeared after a 30 minute ride.  

If you guys think its warranted, Ill get the larger seal and replace it again.

Thanks.  

[Justin B.]

The silicone may last for years, or maybe fail next week...  I would file this info away and if it starts leaking again make sure your local "stealer" gives you the right seal or go to a bearing house and specify a seal by size after you measure the bore to be sure.  I decent set of 6" calipers can be had for under $20 and will measure both metric and standard and I think everybody should own a pair...

[nothing]

That is definitely the wrong seal for an R65. The correct BMW part number is 23121338740. The parts guy did you wrong.

I'd be willing to bet that the silicone fix won't last long. The extra millimeter all around the OD is a huge gap for RTV, plus the ID is tighter on the shaft - meaning the whole seal will be trying to twist with the shaft, rather than being held stationary in the transmission bore like it is supposed to be. You have a limited number of shifts before that silicone is twisted loose.