Final drive rebuild

[Bendy toy]

From what I read here about the final drives - If a bearing collapses and bits fall inside they will mangle the gear teeth. It could be well stuffed inside there.

 

[patzx12]

Check your FD at regular intervals, the rear wheel locking up is not good.
I spin the rear wheel and listen for any noise (make sure pads are not rubbing. All should be silent, also check for excessive backlash. The condition of the oil is also a good indicator.

 

[FENNER]

Check your FD at regular intervals, the rear wheel locking up is not good.
I spin the rear wheel and listen for any noise (make sure pads are not rubbing. All should be silent, also check for excessive backlash. The condition of the oil is also a good indicator.

What would be considered as "excessive" backlash ?

Thanks

 

[Mr Bean]

You're telling me the rear locking up isn't good - i came to a halt in front of an arctic in lane one!

If you look at the VOSA web site the incident should be reported - no warning, not service related and big risk of serious injury.

The wheels are spun each time I clean it and was perfectly smooth last time it was cleaned.

Oil was changed at the correct interval.

But the bike was rear ended last year at 30mph (me stationary) and my suspicion is that there was maybe damage to the crown wheel and pinion - a certain dealer not too far from me says their [rudimentary] checks at the time confirm there was no damage, despite the fact that the wheel and tyre needed replacement and there damage to the footrest hangers which required 're-aligning'.

 

[patzx12]

I think a buddy buddy system is good , get 2 bikes together and compare. There is a spec for it, i will try and dig it out.
I have a GS and a GSA so it helps.
Failing crown wheel bearings would be easily detected with roughness, play and slight noise. if the pinion is on the way out it will be excessive backlash and faint noise. An oil change will confirm.
Look up my thread, "Inside my FD"

 

[Mr Bean]

Funnily enough I read through your rebuild a couple of weeks ago - excellent it is too.

There is still no more than 1mm of rock at the wheel and there appeared to be the same backlash as when I bought it last March - it certainly appeared to be no clunkier when rolling on and off the throttle. The wheel still seems to have the same backlash but as it only possible to turn it a fraction of a degree I'm not sure if it is an indicator of how much there is.

My experience on R1200's is limited but the bike seemed no different to the only two others that I have ridden.

As the bike had a full dealer service history and bought from a BMW dealer I assumed they were all like that.

You buddy suggestion may have highlighted a difference.

I have done 18,000 miles on it since last March (including 3 months off for 2 operations on the broken wrist), I like to think I would have noticed if there was any difference, depends on how subtle the changes would be.

Any specs that I can use would be helpful, thank you.

 

[birdseye]

What would be considered as "excessive" backlash ?

Thanks

the BMW spec for the max side play is 0.3mm measured at the rim by dial guage. There is no spec for the radial backlash apparently. Allegedly. According to Bath Road Motorcycles. There is no backlash adjustment mechanism ie no shimming and since every crownwheel and pinion will be a bit different, so will be the backlash. That being the case it makes sens that there is no spec since there is no adjustability. All of which is a bit surprising

 

[Mr Bean]

It was at the dealers last week because of another issue which required them to take it for an extended road test and nothing was reported at that point - other than they couldn't find the fault that it went in for.

Therefore, if an experienced, BMW trained mechanic didn't notice a fault does one assume it was a sudden catastrophic failure that gave no indication?

 

[jwpzx9r]

You're telling me the rear locking up isn't good - i came to a halt in front of an arctic in lane one!

If you look at the VOSA web site the incident should be reported - no warning, not service related and big risk of serious injury.

The wheels are spun each time I clean it and was perfectly smooth last time it was cleaned.

Oil was changed at the correct interval.

But the bike was rear ended last year at 30mph (me stationary) and my suspicion is that there was maybe damage to the crown wheel and pinion - a certain dealer not too far from me says their [rudimentary] checks at the time confirm there was no damage, despite the fact that the wheel and tyre needed replacement and there damage to the footrest hangers which required 're-aligning'.

I'm no engineer but a stationary bike being hit at 30 mph from behind sounds like a very good reason to suspect that the diff/ drive train could be damaged by the impact. If for example the impact was not in exactly 90 degrees to the plane of the spindle, then the chances are there will have been some twisting moment on the whole assembly. It would be too easy to simple spin the wheel and not detect the possible damage to the drive train. I would be very interested to know the outcome of your problem please post the result of the inspection. The main thing is you are un injured and bikes can be sorted

 

[Mr Bean]

I'm no engineer but a stationary bike being hit at 30 mph from behind sounds like a very good reason to suspect that the diff/ drive train could be damaged by the impact. If for example the impact was not in exactly 90 degrees to the plane of the spindle, then the chances are there will have been some twisting moment on the whole assembly. It would be too easy to simple spin the wheel and not detect the possible damage to the drive train. I would be very interested to know the outcome of your problem please post the result of the inspection. The main thing is you are un injured and bikes can be sorted

I wasn't happy with the bent pieces being 'realigned' but was informed by my solicitor that if the engineers view was that it could be repaired as good as new then I had no recourse to veto it. To be fair it did track straight with my hands off the bars post-repair.

This is the question I posed to the dealer who repaired the bike:

"I am concerned that there was damage caused to the crown wheel and pinion when the bike was involved in the accident. Can you please confirm what checks were undertaken to ensure that the damage was limited to the wheel and tyre and that there was no damage to the internals of the final drive?"

I will not post their response but it is my view that anyone with a moderate understanding of mechanical engineering would consider their actions insufficient.

I have other reasons to question their abilities too. For example, the bike was running on its side for a while after the accident - I was concentrating on the wife (the bike laying on her leg and there is no auto shut-off on the RT) and it ran for a while whilst I suspect there was no oil at the pick-up. The low oil pressure warning has intermittently flashed since on four occasions when idling and temp is around middle on the gauge. The bike has been back twice and they have been unable to replicate it, and therefore correct it under the warranty or insurance repair. It was reported before the warranty expired.

I filmed it on my mobile (from the M25 the other night) and sent it too them today for comment.

I have calmed down now and am grateful that there was no injury.

 

[birdseye]

I cannot imagine any damage from running on its side that would cause an intermittent oil pressure problem. Much more likely that it is a wiring or sensor issue. A bike which ran after losing oil pressure would damage bearings and the failure would most likely be catastrophic. Or to put it another way, if it runs OK now I should not worry other than to get the flashing light sorted out.

You dont really seem to have a problem with the rear drive set up and an engineer has said it is OK. Problem is your loss of confidence. It would be easy for you to talk yourself into thinking that any damage to the final drive was passed along the shaft to the gearboix and then maybe the engine and then maybe .... If you see what I mean.

Best answer to a loss of confidence is to flog the bike and replace. You arent going to get the insurance company to give you a new bike.

 

[Mr Bean]

I cannot imagine any damage from running on its side that would cause an intermittent oil pressure problem. Much more likely that it is a wiring or sensor issue. A bike which ran after losing oil pressure would damage bearings and the failure would most likely be catastrophic. Or to put it another way, if it runs OK now I should not worry other than to get the flashing light sorted out.

You dont really seem to have a problem with the rear drive set up and an engineer has said it is OK. Problem is your loss of confidence. It would be easy for you to talk yourself into thinking that any damage to the final drive was passed along the shaft to the gearboix and then maybe the engine and then maybe .... If you see what I mean.

Best answer to a loss of confidence is to flog the bike and replace. You arent going to get the insurance company to give you a new bike.

For a number of reasons I didn't go in to the issues in great detail, however:

The oil light flashing has only occurred when the bike has idled or moved slow for an extended period i.e. in London traffic and at idle.

I agree that it is more likely to be problems with the big ends/mains if there was a lack of oil. Funnily enough it rattles from cold until the oil light goes out - in my previous life working with engines that would indicate big ends as mains tend to rumble. However, being told it had 5 bar pressure at idle when hot makes me suspicious - the relief valve opens at 6 bar.

Either way I don't care as the dealer has had it twice to diagnose the problem and the oil light still comes on when hot at idle - according to the handbook it has low oil pressure and I should not ride it. Oh, that and the fact that the dealer said it lost 750mls of oil from when it was collected to when it reached their workshop leaves me suspicious. I checked it twice before it was collected - the level was just under half way down the window and the oil light was out when their driver rode the bike on to their vehicle.

Not sure what you mean by: You dont really seem to have a problem with the rear drive set up and an engineer has said it is OK.

The rear wheel will not turn - either in or out of gear. It has remained locked up, it cannot be ridden.

Tell me, how much confidence would you have in your bike if the rear locked up whilst riding on the M25 when wet at night during the rush hour - particularly when you stop in front of an artic?

I am happy to have it back with a new final drive - would you?

What I am not happy with is paying £1,200 for ineptitude or a latent problem that should be covered by BMW.

Apologies if this is kind of direct but I feel strongly that someone should put their hand up and say 'sorry, let's sort the problem'

 

[jwpzx9r]

I cannot imagine any damage from running on its side that would cause an intermittent oil pressure problem. Much more likely that it is a wiring or sensor issue. A bike which ran after losing oil pressure would damage bearings and the failure would most likely be catastrophic. Or to put it another way, if it runs OK now I should not worry other than to get the flashing light sorted out.

You dont really seem to have a problem with the rear drive set up and an engineer has said it is OK. Problem is your loss of confidence. It would be easy for you to talk yourself into thinking that any damage to the final drive was passed along the shaft to the gearboix and then maybe the engine and then maybe .... If you see what I mean.

Best answer to a loss of confidence is to flog the bike and replace. You arent going to get the insurance company to give you a new bike.

You have clearly not read this mans post properly! There is defo a problem with the drive train that needs sorting and yes a lock-up on a major motorway at a busy time of day is goig to dent your confidence, but confidence does not appear to be the root of the problem it's mechanical!

 

[Mr Bean]

You have clearly not read this mans post properly! There is defo a problem with the drive train that needs sorting and yes a lock-up on a major motorway at a busy time of day is goig to dent your confidence, but confidence does not appear to be the root of the problem it's mechanical!

Thanks.

The only lack of confidence I have is with the quality of the repair from when we was shunted in to the back of a van.

The wife and I went on 12 day tour of the Alps and Dolomites in May and June along with 20 other bikes. Confidence in my bike, the way it rides and my ability is not the issue here.

 

[birdseye]

For a number of reasons I didn't go in to the issues in great detail, however:

The oil light flashing has only occurred when the bike has idled or moved slow for an extended period i.e. in London traffic and at idle.

I agree that it is more likely to be problems with the big ends/mains if there was a lack of oil. Funnily enough it rattles from cold until the oil light goes out - in my previous life working with engines that would indicate big ends as mains tend to rumble. However, being told it had 5 bar pressure at idle when hot makes me suspicious - the relief valve opens at 6 bar.

Either way I don't care as the dealer has had it twice to diagnose the problem and the oil light still comes on when hot at idle - according to the handbook it has low oil pressure and I should not ride it. Oh, that and the fact that the dealer said it lost 750mls of oil from when it was collected to when it reached their workshop leaves me suspicious. I checked it twice before it was collected - the level was just under half way down the window and the oil light was out when their driver rode the bike on to their vehicle.

If it actually had 5 bar ( ie 70psi) pressure at hot idle I would be very surprised indeed, but it would certainly indicate that the issue was a sensor rather than the engine. Much more likely the engine is running too low an oil pressure at idle and as you say that could easily be something like wear on the mains or elsewhere due to temporary oil starvation. Its a PITA that you have to do it but you really need a second opinion from another garage and best tested when you are there to see the pressure reading.

Not sure what you mean by: You dont really seem to have a problem with the rear drive set up and an engineer has said it is OK.

The rear wheel will not turn - either in or out of gear. It has remained locked up, it cannot be ridden.

Tell me, how much confidence would you have in your bike if the rear locked up whilst riding on the M25 when wet at night during the rush hour - particularly when you stop in front of an artic?
'

Apologies - I misunderstood your problem / didnt read enough of your post. A lock up that is still locked up ( ie is not a rider perception) is simply unacceptable. And the solicitors comment isnt much use either.

If the dealer wont come to the party there is little you can do initially. In your position and with no dealer cooperation I would take the bike to another dealer and get it repaired properly recording every step of the way. Then sue the first dealer maybe using a decent solicitor. After all, as the bike is now its no use and unsaleable. If I'm understanding you right this time.

 

[Mr Bean]

Hey, no worries.

I have asked on here and now the dealers for the thread of the oil pressure switch so I can buy a decent oil pressure gauge and sender, something like VDO and measure it myself. A hot figure of 5 bar at idle and the relief valve opening at 6 bar is (to me) implausible.

A couple of further points.

a) Two oil changes ago I fitted a magnetic oil drain plug when completing a change, the following change it had what I would consider significant particles attached to it. As it had not been fitted with one previously I took the view to wait until the next change.

b) I also sent an oil sample to Blackstone Labs in the USA who confirmed there were elevated levels of a number of metals in the oil but suggested sending another two samples to see if there is a trend and it is worsening.

c) They changed the oil light switch last time saying it was faulty and causing the flashing - I have sold 1,000's of car (I would guess the same construction) ones down the years and the only fault that I saw was that they leak, mine wasn't leaking.

To be fair to the solicitor, we were not discussing the final drive. He's fully supportive that this is either a post-accident repair problem or BMW's - either way he feels I'll get my money back in the settlement as worst case scenario, but I've already shelled out £1,000's that will not be payable until we reach a final agreement with the other drivers' insurers. I am trying to keep the cost to a minimum.

If, through my negligence, I bought a pup then I am happy to accept it - as I have over the rear ESA being fooked. But what does cause me issues is that it could very well been much more serious the other night and the dealer is distancing themselves as far as possible from it.

The last 10 meters or so was with the bars counter-steering trying to keep it upright!

 

[Mr Bean]

Update.

As the dispute with the Motorrad dealer continues I thought I'd peel back the gaiter to see if there was any damage to the drive shaft.

The lock up was caused by the universal joint (UJ) disintegrating.

I looks as though the failure may have been caused by a failure of the gaiter to stop road crap getting in to joint or the wheel being shunted so far forward so that the bearings in the UJ took the impact.

If there is sufficient fore and aft movement in the drive shaft so that the shaft could not "bottom out" in the event of a rear impact then I am happy to accept it was not accident related. The question then is was it a 'latent' defect that was there when I bought the bike from the Motorrad dealer - if so, BMW UK are still liable for it. If not I'll cough for it.

So, since the accident I have noticed or repaired:

a) rattling on start up - 'they all do that sir'
b) flashing oil light at idle when hot - unsuccessfully repair attempted twice and still flashing.
c) rear ESA packed up - replaced at my expense
d) leaking hub seal - replaced
e) failed drive shaft

I am keen to learn if it is possible for the shaft to, in effect, 'bottom out' by the wheel trying to pivot too far forward and transfer the impact to the bearings in the joint - anyone know?

I am guessing that the gaiter also acts as a bump stop.

I will probably sell the bike as the wife is no longer confident of riding pillion on it.

 

[autogs]

i had an 08 gsa that had a broken up uj at the fd end,i noticed it before it got to bad though.im surprised you didnt notice xtra backlash in the rolling on and off the throttle before it locked up.as for the gaiter acting as a bump stop,no thats not its function at all.

 

[Bendy toy]

The swingarm linkage should stop the FD moving backwards so the dealer is talking bullocks.

 

[Mr Bean]

Thanks.

No, I didn't notice the backlash. Neither did the Motorrad mechanic who rode it a short while before it disintegrated - if he/she did they didn't tell me about it.

I appreciate the gaiters' primary function is not being a bump stop, but what then stops the rear pivoting too far forward in the event of a rear shunt?