new shift shaft seal leaking

[rob650]

Installed a new shifter shaft seal during my spline / swingarm maintenance and now it leaks.  I've pulled it out again and examined it, doesnt look damaged.  Is there some trick to this?  I have the "ridged" side towards the trans and the "flat" side towards the shifter.

I should have left it alone!  the old one didnt leak, i just thought it would be good change it out since I was going to the dealership anyway for other parts....argh.

Other than that, really starting to enjoy the smell of 75w90...

[nhmaf]

I cannot recall offhand which end goes in first, but MrRiden or someone else will probably chime in soon with the answer.  It is important that the seal goes in straight and is fully seated.   I'm not sure if one can re-use one after it has gone in and been pulled out again?

[Bob_Roller]

The side with the spring visible goes in toward the transmission.

So it sounds like you have it in the correct way.

How far in did you install it ?

I think if you install it too far in, it might leak, as the shift lever has a 'seam' where it contacts the mating part in the transmission.

Did you by chance look at the surface where the seal sits, gouges or pitting may cause leakage in that 'bore' area.

Check the allen head bolt that hold the shift lever on, to see if it is tight.

If the seal is in crooked enough to leak, it should also be causing shifting problems, ask me how I know this little fact !!!!!

[rob650]

There's a spring?

the bore and the internal area looks unscratched and clean.

[Bob_Roller]

There's a small diameter spring on the inside of the seal, that keeps tension on the area where the seal contacts the shift shaft.

[rob650]

pulled the seal again - no spring.  I don't see it as a seperate piece on the microfiche so maybe I got a bad one.

[Bob_Roller]

I know the seal that is currently installed in my gearbox, has the spring, and the spare seal that I got from the shop that did the overhaul on the gearbox 2 years ago has a spring.

Looks like you may have gotten a bad part.

[rob650]

dang, back to the dealer

[MrRiden]

Bob, who is my grand pooh-bah of shifter seals, has my complete agreement. If yr seal has no spring it is defective. The spring helps to keep tension on the seal lip which is a bit floppy without the extra support. Ok, not very technical but everything needs to be clean, smooth and straight as well as complete. The spring is an integral part of the seal and if you have the old one you may be able to see it. What methodology did you employ to install it [ how'd ya bang the bugger in]?
rich
who hates the smell of gear oil

[rob650]

Thanks MrRiden and Mr Roller

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 (not too tight).  As it is, its not a super snug fit on the shaft, I can see why the spring is needed.  

Of course, I threw out the old one that I removed when I cleaned up my workbench last week.  Lesson Learned.

This part came wrapped it its little BMW sealed baggie without any spring, I'm concerned this (lack of a) spring thing will be an issue when I try to exchange it.

[Landlubber]

Just a point to note if anyone is interested.

Yes the seal has a little spring that tensions the lip.

Did you know that if you pry out the seal spring, it can be easily undone by twisting it at the joint, a snip with pliers can shorten the spring putting more tension on the shaft lip section, just twist it back on when snipped.......not saying to do this, but I am a boatbuilder, we have to do all sorts of funny things sometimes to correct problems.

[rob650]

SO, my new seal DOES have the little internal spring, and still leaks.  The BMW parts guy says to run a bead of RTV ? sealant around the outer edge of the seal before installing the shifter shaft.

Have never used this product before, is it made to withstand exposure to petroleum? (the trans oil)?  Special kind I should get?   Thanks Everybody.

[Bob_Roller]

How long of a ride does it take for the seal to start leaking ?

Does it leak statically without ever having ridden it ?

Does the surface of the shifter shaft look OK, no obvious damage, gouges, grooves, etc.?

How far in are you installing the seal ?

My last best place to go after this, is the negative battery lead where it is bolted to the transmission, the bolt is hollow, or should be hollow, it is the vent for the transmission, check it for obstructions.

A wild guess here is that when the transmission gets up to operating temperature, it is 'pressurized' due to the heat, and air can't escape, and the shifter shaft seal may be the 'weak link' in the system.

[rob650]

Bob,

With the shaft and seal installed, as soon as I add trans fluid to the tranny, in a minute a small drop starts to form on the bottom outside edge of the shifter housing.  If the bike just sits there, I'd lose a few ounces per day.

The shifter shaft to me looks in fine shape, no chinks, gouges, or scoring.

Not sure what you mean by how far in...the seal gets "sandwiched" between the trans housing and the shaft, yes?

Checked that bolt earlier when doing the spline lube, its AOK.

Thanks.

[nhmaf]

Is it possible for you to post a pic?   I'm not sure but we may be entering the realm where a pic or two might help alot.  The seal has to go inward a certain amount to do its job, but pushing it too far (or not far enough) might result in leaks.