Final drive strikes at last!

[Grim Rider]

Soon after I joined this forum and read all about the possible final drive failure I bought a new bearing and oil seal from Motorworks, on the grounds that if I had the parts reversed sod's law would mean I wouldn't need to use them. It has worked - until now!

Last night heading down the A14 the GS started to feel 'graunchy' as I came off a roundabout, otherwise running fine. Stopped at the services just south of Kettering, clunk from rear as I changed down gear, and found oil dripping from final drive and streaks around tyre. Waited 3 hours for AA (luckily in warmth of the Little Chef - staff were great, even finding a charger for my mobile which died as soon as I phoned Carole Nash!) before warm trip home.

I know this is nothing new to many of you but it is still a shock when it happens the first time - bike had just got to 88k and I was thinking of how I had not a single problem with it in the 70k I have covered on it. Now having to reacquaint myself with all those final drive threads - thanks again in advance Steptoe!

 

[Timolgra]

Not everyone agrees with me but I always change the bearing at less than 30K miles.
In 11 1/2 years I've never had a problem, of course that's either down to luck or preventive maintenance. Anyone's guess

 

[(RIP) DitchWater]

I was looking at those threads myself yesterday, whilst checking out the paralever (pivot) bearing threads, and I thought at over 70k and no information about the FD being serviced I'd better have a look in there as well because I suspect there's been a change in the feeling of the rear wheel in corners.

My only question, for now, is how does the shimming work?

I think I'll have to buy the factory manual.

 

[Grim Rider]

I have always worked on the basis that if it ain't broke best to leave it alone. I have changed the final drive oil every time I changed the engine oil and checked it for anything amiss. The other advantages to changing the bearing regularly would be one I would know what I was doing by now, and two I am sure everything would come apart a lot easier than it is proving to having never been apart in ten years!

 

[Welshman]

I have always worked on the basis that if it ain't broke best to leave it alone. I have changed the final drive oil every time I changed the engine oil and checked it for anything amiss. The other advantages to changing the bearing regularly would be one I would know what I was doing by now, and two I am sure everything would come apart a lot easier than it is proving to having never been apart in ten years!

Mine generally gives me warning, little oil spots on the rear rim (I generally ride in dust not road grime, it has been at around 35,000 miles in each case (much of my milage is not tar

 

[(RIP) DitchWater]

Well, I definately need to do something about my pivot bearings, which at first will be an adjustment, and when my parts arrive will be a replacement.

However, at over 70K miles I have noticed the rear wheel does not feel as smooth as it used be, and I have given it a bit of a hammering this year with some off roading: Not 1000s of miles but certainly rough in places and since the FD off I'm going to have a look.

Because it's not leaking now it doesn't mean there isn't a problem developing. I found that nugget after reading many threads here and elsewhere.

So my original question still stands in that there are shims available for the FD output bearing in many sizes and therefore, how do I determine which size I need or do I simply reuse whichever shim is already in place?
And the second question which comes from this is do I need to re-evalute which shim to use because I am using a new bearing?

The third question will be where do I take those measurements, but I'll save that until later.

 

[tosh23]

Rob,
I think Shaun ( little toe ) lives near you, He could do it in his sleep mate..
Ps Hope you wasnt on an IBA ride......Tosh

 

[Dazlove]

Final Drive

Not everyone agrees with me but I always change the bearing at less than 30K miles.
In 11 1/2 years I've never had a problem, of course that's either down to luck or preventive maintenance. Anyone's guess

I do exactly the same, changed every year at approx 30k........except this year went it failed at 18k

Hope you get it fixed soon

Regards

Dazlove

 

[Grim Rider]

Rob,
I think Shaun ( little toe ) lives near you, He could do it in his sleep mate..
Ps Hope you wasnt on an IBA ride......Tosh

Last leg of the October Outing - debated whether to continue on to Naseby but decided best not to let it get any worse so baled out. Got it apart today (two of allen bolts just rounded and I had to chisel them out - luckily had ordered a few spare for some reason!), and got the bearing off with some help from local bike shop's vice. Crown in freezer now so will put it back together tomorrow and hope all okay!

 

[tosh23]

You must admitt you have been lucky with your bike mate, at least it wasnt on a gold run..
Looks like you will be back on the road soon..I havent done a rear yet but it looks fun to do....Tosh

 

[MikeP]

So my original question still stands in that there are shims available for the FD output bearing in many sizes and therefore, how do I determine which size I need or do I simply reuse whichever shim is already in place?
And the second question which comes from this is do I need to re-evalute which shim to use because I am using a new bearing?

The shims, unless badly scored, can be re-used. They are really there to compensate for variables in the machined housing rather than the bearing.

 

[warmshed]

Hi, hope it goes well. I found this video sequence for the rebuild, takes a little time to download but very good, will help you check to see if the shimming is correct or needs to be adjusted. You don't want to replace the bearing and find it fails again due to incorrect assembly.

http://www.bmwlt.com/uploads/lt_final_drive_rebuild.wmv

Hope it helps, Dave.

 

[(RIP) DitchWater]

The shims, unless badly scored, can be re-used. They are really there to compensate for variables in the machined housing rather than the bearing.

Thank You Mr P. That's the information my Paynes manual doesn't cover and after ploughing through several internet fora, I was still non the wiser.

Hi, hope it goes well. I found this video sequence for the rebuild, takes a little time to download but very good, will help you check to see if the shimming is correct or needs to be adjusted. You don't want to replace the bearing and find it fails again due to incorrect assembly.

http://www.bmwlt.com/uploads/lt_final_drive_rebuild.wmv

Hope it helps, Dave.

Thank You Sir. It'll be better than the F1 race which is just starting: You can't beat a bit of metrology on a Sunday morning.

 

[tosh23]

Dear Warmshed,
I have been looking for that video for over 3 years, He cracks me up with his use of words. I wish I could talk like that..Fantastic video THANKYOU

 

[warmshed]

Glad you like it, Funny, who would normally start a final drive rebuild video with a few shots of their horses???

 

[Grim Rider]

Hi, hope it goes well. I found this video sequence for the rebuild, takes a little time to download but very good, will help you check to see if the shimming is correct or needs to be adjusted. You don't want to replace the bearing and find it fails again due to incorrect assembly.

http://www.bmwlt.com/uploads/lt_final_drive_rebuild.wmv

Hope it helps, Dave.

Thanks Dave - was very useful, especially with putting it all back together today. Put crown in freezer, bearing in oven for 10 minutes and went straight back together like it was supposed to. Also heated cover up in oven and it made putting it back together over the bearing simpler. I followed what he says about shimming but having no way of measuring it (guessing would be harder with final drive still on the bike too) I reckoned shim that was already in it should be okay after doing the job fine for 10 years - certainly no lateral movement I could discern when it was back together. Whole job only took a couple of hours and was far easier than I had feared!

 

[warmshed]

Well done glad it turned out OK. My GSA is running well so I have downloaded the video clip to a CD in the hope Ill never need it! Though I was itching to try it as the video made it look so easy and interesting.

 

[Micky]

Cleaned and re-greased my chain today

 

[tosh23]

Its a shame that the video isnt a sticky or somthing