Gearbox leak - not again...

MattW · Apr 20, 2009

Just washed my bike and thought I'd pop the swingarm to FD boot off too make sure everything was ok with my replaced gearbox output seal:
http://www.ukgser.com/forums/showthread.php?t=180313

However....

<a href="http://picasaweb.google.com/lh/photo/KjvzbSWDB_TQV5GMIbIFQg?feat=embedwebsite"><img src="http://lh5.ggpht.com/_SSn2CtCOKnU/SezIgZhPgRI/AAAAAAAABlM/i5uh8mp5_rk/s800/IMG_4391.JPG" /></a>

F*ck, f*ck, f*ck

I've checked levels in the gearbox and FD and it's come from the gearbox - about an eggcup more than what's shown in the picture (I wasn't expecting any and didn't have a bucket ready

) - probably 250mm or so.

I did about 50 miles after changing the seal and popped the boot - bone dry, Since then I've done about 350 miles before checking tonight. The seal replacement appeared to go by the book, but obviously it didn't.

So, two questions...

1. Am I likely to have fecked my gearbox running it low on oil?

2. What in God's name did I do wrong?

To be honest, I'm pretty gutted and am losing the love a bit (and my 'get healthy, no midweek drinking' plan has gone out of the window and I've just been and bought a case of beer).

Stewart H · Apr 20, 2009

Bugger ! I thought that was sorted, I should not think you have done any harm in that distance, what oil was in it? I have heard that they can leak with some types, why not top it up and ride for a bit to prove its otherwise undamaged.
Stewart

street_moto · Apr 20, 2009

Bo••ox! Hard luck Matt!

You didn't change to a fully synthetic did you?

Nowt worse than thinking a job's gone well then finding it's the same as before!

Hope you get it sorted! :comfort

Keep us posted!

Regards Dave

MattW · Apr 20, 2009

Stewart H said:
Bugger ! I thought that was sorted, I should not think you have done any harm in that distance, what oil was in it? I have heard that they can leak with some types, why not top it up and ride for a bit to prove its otherwise undamaged.
Stewart

Thanks Stewart

I hope I've not damaged it - that would be the final straw - only time will tell I guess. It's a much worse leak than previously - only a few drops then, but it's best part of a mugfull in 300 miles now

I can't leave that without finding out what's happened. All I can think is that either the new seal has shredded due to a bad shaft (but the shaft seemed ok to me and the old seal was only leaking drops :nenau

) or the seal has popped out of its housing in the gearbox (can they do that - I set it to the same depth as the one I took out?..)

street_moto said:
Bo••ox! Hard luck Matt!

You didn't change to a fully synthetic did you?

Nowt worse than thinking a job's gone well then finding it's the same as before!

Hope you get it sorted!

Keep us posted!

Regards Dave

Ta Dave.
Nope refilled with mineral 80w90 GL5 (Halfords brand).

Guess I'll be tearing it apart again (when I can bear to look at it again

) - at least I know what to do now...

motobiker · Apr 20, 2009

I'm curious. why would changing the gearbox oil to fully synth have the potential to cause an oil leak. Thats a new one on me and flies in the face of experience to be honest. My previous 1100 used different oils including fully synth with no ill effect whatsover.

MattW · Apr 20, 2009

motobiker said:
I'm curious. why would changing the gearbox oil to fully synth have the potential to cause an oil leak. Thats a new one on me and flies in the face of experience to be honest. My previous 1100 used different oils including fully synth with no ill effect whatsover.

No idea why, but I have read anecdotal stuff on here and ADV from people who switched to fully synth (either engine or GB) and experienced leaks :nenau

Not a factor in my current situation though as I'm on full mineral.... (and its pi**ing out

)

motobiker · Apr 20, 2009

hearsay is wonderful isn't it. fact is our american cousins love using 'redline' which is fully synth and have been using it since the only GS was the 1100.. Many changed from the OE oil never heard this story about it leaking though. new one on me.

MattW · Apr 21, 2009

MattW said:
I've checked levels in the gearbox and FD and it's come from the gearbox - about an eggcup more than what's shown in the picture (I wasn't expecting any and didn't have a bucket ready ) - probably 250mm or so.

I did about 50 miles after changing the seal and popped the boot - bone dry, Since then I've done about 350 miles before checking tonight. The seal replacement appeared to go by the book, but obviously it didn't.

So, two questions...

1. Am I likely to have fecked my gearbox running it low on oil?

2. What in God's name did I do wrong?

Anyone else with any words of wisdom with regard to the likely consequences of running gearboxes low on oil?

If necessary just lie to me and tell me it'll be fine

BigblackGS · Apr 21, 2009

I´m sure you will be fine Matt ! The gear boxes are really solidly built, When i took my geatr box apart i suspect that the tiny spring on the oil seal had either come out of place at some time or been disslodged during fitting, If it is any compensation you have just done the job and know what you are doing this time so it will be much easier, Best of luck.
Phil

ianboydsnr · Apr 21, 2009

That seems a hell of a lot of gearbox oil to come out in such a short while, through a leaking seal, something else is not right, is there a vent on the gearbox :nenau

MattW · Apr 21, 2009

ianboydsnr said:
That seems a hell of a lot of gearbox oil to come out in such a short while, through a leaking seal, something else is not right, is there a vent on the gearbox

My thoughts too, there is a gearbox breather (although I've never actually found it) but the only way oil can get into the swingarm is either from the GB output seal or the FD input seal (gaiters at each end) :nenau

I guess I'll find out when I take the swingarm off (again

).

DrFarkoff · Apr 21, 2009

MAtt if there's a mugful you're probably talking 300cc at the most?

that means there is still half a litre spinning around in there

If you're riding like an absolute loon flat to the Mat everywhere all the time then you may possibly have done something

But I wouldn't think you'd do too much damage in 350 miles if you're riding half sensibly even if it was spirited

MattW · Apr 21, 2009

Phil, Jaythro

Thanks for the reassurance :thumb2

I'm going to try and strip the back end down tonight and see what gives.

cheers
Matt

CHANGELING · Apr 21, 2009

If it is the shaft it can be fixed using a speedy sleeve from SKF the bearing manufacturers. I may have a part number/dimension reference for an 1100 gs raer output shaft somewhere as I did this to mine about 40000kms ago and it has held up perfectly. I stuck it to the shaft with bearing retainer from Loctite.
I used the original BMW rear output seal and fitted it to my rebuilt gearbox while it was on the bench so it must be doable in the bike. I did my as a precautionary though!!! Not as a fix.

D6 · Apr 21, 2009

motobiker said:
I'm curious. why would changing the gearbox oil to fully synth have the potential to cause an oil leak. Thats a new one on me and flies in the face of experience to be honest. My previous 1100 used different oils including fully synth with no ill effect whatsover.

prob cos synth is thinner viscosity?
will leak out of a worn and already leaky seal easier?
if the seal is good it shouldnt leak wi synth, cant CAUSE a leak,

guzzimag · Apr 21, 2009

Nah you'll have done no damage. Still plenty of oil in the box. It'll need a new seal, make sure the seal surfaces are cleaned and lubed when you put them in and, obvious as it may sound, that it's in the right way round. And be careful not to damage the seal lip (oil it before installation) and make sure the output shaft is clean and doesn't have a lip worn into it from the previous seal that could damage the new one again. Bad luck mate!

Mac · Apr 21, 2009

Just read this....BOLLOX

......

i'm no expert with this particular problem but i'm chuffed you caught it in time, it's unlikley you done any damage dude, there's been a gradual loss of oil and im +1 with guzzimag, you'll sort it

But fer fecks sake.............................. :rocketwho

Blue skies... :thumb2

MattW · Apr 21, 2009

Ok - after an evening spent crouched over a hot air gun it's in bits again.

When I removed the swing arm and driveshaft the seal was still in place and apart from the oil lying around, nothing looked wrong. I pulled the seal which looked fine and tried my best to have a really good look at the shaft. I then thought of shoving the camera set to macro in there which made it a bit easier to see the seal land.

There appears to be a slight eroded notch in the shaft - I'm pretty sure the camera makes it look worse than it is, but perhaps that's wishful thinking...

Could this leak 300ml of oil in 300 miles?

<a href="http://picasaweb.google.com/lh/photo/RgcPZPkRdhhYNBHoejCYcQ?feat=embedwebsite"><img src="http://lh3.ggpht.com/_SSn2CtCOKnU/Se4u7Y7j_eI/AAAAAAAABnI/M596qO8og84/s800/IMG_4394.JPG" /></a>

<a href="http://picasaweb.google.com/lh/photo/BZ0gPTtmHW9_49qQ5MgRWw?feat=embedwebsite"><img src="http://lh4.ggpht.com/_SSn2CtCOKnU/Se4vEYkciLI/AAAAAAAABns/tzT_ZHj03aE/seal2.jpg" /></a>

<a href="http://picasaweb.google.com/lh/photo/HLIlUP-1ezEWr6ymqn-dNQ?feat=embedwebsite"><img src="http://lh4.ggpht.com/_SSn2CtCOKnU/Se4vCMd9rfI/AAAAAAAABng/qZzEo3UaQbs/s800/seal1.jpg" /></a>

<a href="http://picasaweb.google.com/lh/photo/qErS-DY_IX1FunCgxwEniQ?feat=embedwebsite"><img src="http://lh6.ggpht.com/_SSn2CtCOKnU/Se4vFhOBMZI/AAAAAAAABn0/ybm6vJkB4Jc/s800/seal3.jpg" /></a>

Any opinions form those who know about this stuff, gratefully received.

cheers
Matt

Stewart H · Apr 21, 2009

It may be a wear groove from the old seal, I have seen applications where its advisable to insert the new seal to a different depth, allowing it to run on a new bit of the shaft, how deep is the register in the gearbox where the seal sits? and how much shaft compared to the thickness of the seal, you may be able to do that, failing that a sleeve like our esteemed friend mentions elsewhere in this thread.
Stewart

DrFarkoff · Apr 21, 2009

If you can't find any defects ??

i.e Is the wee spring on okay around the shaft seal inner lip?

the shaft is not pitted badly I would strongly consider increasing the depth of the seal so that the fresh lip runs on the clean unmarked shaft and not in a groove

Gearbox leak - not again...

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