F.D. failure means what?

[airoilheadbeemerguy]

Hi, have seen numerous posts re final drive failures and it makes me wonder just what people are specifically referring to. I personally do not consider a leaky seal being a final drive failure any more than a leaking rear main engine oil seal is an engine failure. Is this what folks mean when they post a final drive failure? I know there is only a small amount of hypoid oil in the drive unit and ignoring a leaky seal will lead to bearing failures. Some clarification would be helpful I think.:wave

[aaaaaa]

You got it right beemerguy. But IMO a major disassembly amounts to the same thing. The difference being that a catostrophic failure leaves one stranded. BTW belts don't leak.
robert

[reimerdavid]

Hi, have seen numerous posts re final drive failures and it makes me wonder just what people are specifically referring to. I personally do not consider a leaky seal being a final drive failure any more than a leaking rear main engine oil seal is an engine failure. Is this what folks mean when they post a final drive failure? I know there is only a small amount of hypoid oil in the drive unit and ignoring a leaky seal will lead to bearing failures. Some clarification would be helpful I think.:wave

I to would like more information on this subject. I really would like to here from people who had a "Failure'" and had it repaired under Warrenty. Have there been any other Failures after a Dealer Repair ? I'm trying to figure out if the F.D. failure's are a result of poor Q.A. when manufactured, batch of sub-par parts when manufactured, of maybe a poor Engineering design nly time will tell and I HOPE the verdict isn't an Egineering desige flaw.

Dave

[soffiler]

Hi, have seen numerous posts re final drive failures and it makes me wonder just what people are specifically referring to. I personally do not consider a leaky seal being a final drive failure any more than a leaking rear main engine oil seal is an engine failure. Is this what folks mean when they post a final drive failure? I know there is only a small amount of hypoid oil in the drive unit and ignoring a leaky seal will lead to bearing failures. Some clarification would be helpful I think.:wave

Well, since everybody is different, than you can expect everybody's definition of failure to be different.

For the non-Evo drives:
They should exhibit zero play. Some call any discernable play "failure" and it IS a typical signal of impending failure of the crown gear bearing. These drives aren't known for leaky seals as far as I know; when seals leak it's usually created by the excess motions allowed by a failing bearing. Another signal of impending failure is flaky bits of metal in the lubricant. Some microscopic sparkly bits are normal, but flakes are not. Some people might erroneously flag the microscopic sparkly bits as a "failure".

Evo drives:
A small amount of play up to (working from memory) 1mm at the wheel rim is considered normal and is consistent with the design, which differs from non-Evo. Some people might become concerned by the play even when it is within the normal range. These drives seem to suffer a high rate of outer seal failure that is unrelated to internal damage (that is, unless or until enough lubricant is allowed to leak out). Some might label the seal failure as a drive failure. (If the bike is laid up for 5 weeks out of the riding season waiting for warranty repair, there might be certain justification in calling this a "failure") The Evo drive is also known to suffer catastrophic internal failure but frankly I don't know exactly WHAT fails... every one I have ever heard of has been replaced as a unit. I have yet to hear of an overhaul and thus it seems no one outside of BMW has seen the internals of a failed Evo drive.

[deilenberger]

I to would like more information on this subject. I really would like to here from people who had a "Failure'" and had it repaired under Warrenty. Have there been any other Failures after a Dealer Repair ? I'm trying to figure out if the F.D. failure's are a result of poor Q.A. when manufactured, batch of sub-par parts when manufactured, of maybe a poor Engineering design nly time will tell and I HOPE the verdict isn't an Egineering desige flaw.

DaveDave - a rather quick search on "final drive" should turn up extensive threads discussing exactly these issues. The cause of hexhead FD failures hasn't been determined since BMW replaces all defective drives. Failures seem to have greatly lessened or stopped since BMW specified changing the life-time oil at the 600 mile break-in service.

[airoilheadbeemerguy]

Hi, the failure I'm referring to is the seal on the outside of the final drive assembly on the right hand side. If there is another seal leaking back there please advise if you know about it. Thanks.

[bikerfish1100]

Hi, the failure I'm referring to is the seal on the outside of the final drive assembly on the right hand side. If there is another seal leaking back there please advise if you know about it. Thanks.


that would not be a "FinalDrive failure", that would just be a "blown seal" (or whatever variant of "leaking" that you prefer to use). Some FDs have failed- typically the crown bearing fails, tho some will erroneously call an out-of-spec pivot bearing a "FD failure".

[soffiler]

that would not be a "FinalDrive failure", that would just be a "blown seal" (or whatever variant of "leaking" that you prefer to use). Some FDs have failed- typically the crown bearing fails, tho some will erroneously call an out-of-spec pivot bearing a "FD failure".

On Evo final drives? Really? That's one of the first times I'd heard that. Sure, it's true on pre-Evo Paralever FD's. Wondering where you get your info.

[bikerfish1100]

So not on the Evos? fine 'n dandy.
I was just trying to clarify to the OP that a seal failure would not be synonymous with a FD failure.

[soffiler]

So not on the Evos? fine 'n dandy.
I was just trying to clarify to the OP that a seal failure would not be synonymous with a FD failure.


Totally agreed with the point about seal failure NOT being an FD failure.

We know there have been Evo FD failures (witness the hoopla at the Iron Butt '07 and Spank rally '08) but we, er, I have yet to see anyone actually take one apart and share the failure mode with the BMW world at large. It seems the vast majority of them are failing within warranty and BMW is replacing them as a unit.

[marcopolo]

There have been an unknown number, like mine, where the FD had to be replaced because significant play developed where the wheel flange (what wheel bolts to) and the axle tube mate -- a friction fit. That's what holds your rear wheel on, so not to be taken lightly. When these two parts wear away, the fix for my RT, and others I've read about, was to replace the final drive (flange comes with the FD), along with the rear rotor and lug nuts -- all under warranty. Obviously, in this sort of failure there's no fluid leak, or anything of the sort, just metallic residue on the wheel and play that far exceeds the allowed 1mm. In my case, it happened on a long road trip, and when I (along with friends), removed the circlip, the wheel/flange came off with absolutely no "friction" whatsoever. That meant the only thing holding my wheel on the bike was that small circlip. Yikes, not a comfortable feeling.

[bikerfish1100]

daaammn.

[soffiler]

Mark/marcopolo: As an amateur collector of anecdotal FD failure info, yes, I am aware of that failure mode. To be perfectly honest, I believed it to be an early-batch problem. I am slightly surprised to see it on an '06 model; duly noted.

[marcopolo]

Mark/marcopolo: As an amateur collector of anecdotal FD failure info, yes, I am aware of that failure mode. To be perfectly honest, I believed it to be an early-batch problem. I am slightly surprised to see it on an '06 model; duly noted.

It happened July 2007, when the bike had been in service for 15 months and 38,000 kms. This failure was the subject of an early 2005 technical service bulletin relating to the GS (the only hexhead model on sale at the time if I recall correctly). A fellow from Kansas on another Board I frequent had the same problem a number of months after mine, only in his case BMW USA refusesd to replace his FD. Instead they had the dealer obtain some sort of special tool to determine whether they could simply replace the flange and not the entire FD. Interestingly the service bulletin from 2005 was quite explicit in stating that the FD had to be replaced because in all likelihood the splines on the axle tube would have been worn down too, and not just those on the flange. I'm not sure why they apparently changed their view on that (other than to save the expense of a new FD).

BTW, my second FD now has about the same number of KMs of use as the first when it failed. No signs of play in the wheel whatsoever. I was told by BMW of Salt Lake, where my bike was repaired in 2007, that the job (parts and labour) would have been the better part of $2,000 had I had to pay out of my own pocket.

[47512]

Gear mfg's put phosphorus on new gears to help them mate together during break in, as it wears off it floats around in the oil, and left in long enough can, I say can, because it is not always so, it can be abrasive to oil seals. There is a small volume of oil in motorcycle finals, the concentration of phosphrous can be quite high, probbaly why BMW wants it drained after a short break in period.

Ken G.

[TwoWheels2Go]

Gear mfg's put phosphorus on new gears to help them mate together during break in, as it wears off it floats around in the oil, and left in long enough can, I say can, because it is not always so, it can be abrasive to oil seals. There is a small volume of oil in motorcycle finals, the concentration of phosphrous can be quite high, probbaly why BMW wants it drained after a short break in period.

Ken G.

In my book, a FD failures is damage/wear to gears/bearings in final drive that require replacement of one or both. I replace final drive oil every other engine oil chanage and look for metal on the plug. Dealer checked my bike: no filings, no wheel play, no oil leaks. Every time I starto out, I look for oil leaks. 4,500 miles later a loud grinding noise. Repair included final drive assembly, drive shaft and 2 u-joints (44,000+ on a 2007 K1200LT). I am not impressed with how BMW fixed the non-problem at my expense. :(

[Greenwald]

Hi, have seen numerous posts re final drive failures and it makes me wonder just what people are specifically referring to. I personally do not consider a leaky seal being a final drive failure any more than a leaking rear main engine oil seal is an engine failure. Is this what folks mean when they post a final drive failure? I know there is only a small amount of hypoid oil in the drive unit and ignoring a leaky seal will lead to bearing failures. Some clarification would be helpful I think.:wave

Your final sentence says it all. The clarification you seek can only come from BMW, and they have been 'mum' on the subject. "FD failures? What FD failures?"

A leaky seal is a leaky seal. Don't ignore it - bigger headaches will follow!

As for actual FD failures, that has become a 'war of semantics.'

Mine puked at less than 50,000 miles, so I've been there. :dunno

[racer7]

I don't recall ever seeing anyone on this site call a seal failure an FD failure. A crapped out seal is just that, no more. For the one that usually fails- simple repair, $31 part, no big deal. Heck, it can be done roadside if necessary.

Not yet mentioned but familiar to most of us is the fill volume change for the non-vented current FD design. Down to 180 ml. The drives get hot enough to build some internal pressure and an overfill can lead to an early seal leak. From personal experience I can tell you that at least some dealers are sloppy on fill volumes, having pulled over 260 ml out of mine once (more than the factory original amount that got reduced to 180). So I suspect a bunch of the seal failures simply come from failure to measure accurately and follow the factory procedure. About 1/3 of so-called professional mechanics work does not meet my stds so I generally do my own and am very careful about who I let touch my stuff when I can't.

I think the key reasons true FD failures are constantly discussed as a BMW brand negative are 1) comparisons to car FDs that typically go whatever the life of the vehicle is with no problems so are both maintenance and trouble free, 2) the safety issue of a failed FD on a bike and 3) the inconvenience and cost of getting stranded on a long trip given that BMW has deliberately reduced its dealerships which were scarce to begin with and the fact that it has taken as long a 2 weeks to actually get a replacement FD as reported by some- and the $2K cost.

Having said that, the FD on my 08 RT is OK but the bike hasn't hit 50K yet. I change the FD lube every time I change the rear tire mostly to inspect the lube for any telltale signs of wear- so far it just coms out clean with the usual tiny bit of stuff on the magnetic plug.

My candidate for the worst system on a BMW is not the FD- it is instead the fuel storage and dispensing system which has a long list of bad engineering choices and poor parts selections- and the lots of safety issues that have actually burned some bikes to scrap. AFAIK, they haven't roasted any riders though.

[lkchris]

As a longtime Airhead rider, it's a bit of a transition to get used to fuel injection and the surging and instant fuel shutoff it creates. I know I've put some real shocks into my drivetrain in "unsmooth" moments.

Yes, the fluid capacity change is important and also with this came inclusion of fill and drain plugs, which weren't on the early versions. That IMHO mostly to placate all the "oil geniuses" in the customer base. Mercedes has brought back engine oil dipsticks, I think BMW cars not yet.

I'd say worst engineering "problem" is need to periodically grease transmission input splines--that's NEVER required for cars, but has been a BMW glitch for generations.

[Ctrod]

My FD failed 40 days before I was leaving for vacation, Unfortunately it took the dealer 44 days to fix it. And it was a lot more then a seal. I needed a whole new FD. At least the new one has a drain plug to change the oil.

[deilenberger]

I'd say worst engineering "problem" is need to periodically grease transmission input splines--that's NEVER required for cars, but has been a BMW glitch for generations.

Kent - I'd rate that as a non-issue/non-glitch on hexheads.

I can't recall more then one complaint about clutch spline service or failures on the forums, and many people have over 100k miles and the splines have never been touched. Earlier model bikes that did have problems were usually (eventually) tracked back to alignment problems with the engine/tranny input shaft - it seems BMW may have gotten a handle on that problem with the R1200/hex engine/transmission.

[norvillnh88]

I think we are being unduly harsh on Die BMW-Motorrad-Gesellschaft, they just needed a few years to sort out the glitch.

[Greenwald]

I think we are being unduly harsh on Die BMW-Motorrad-Gesellschaft, they just needed a few years to sort out the glitch.

Unfortunately, you should have said "....a few MORE years to sort out the glitch."

R1200RT's much newer than your '07 have had inexplicable low-mileage FD failures already.

Problem hasn't gone away. :violin

[deilenberger]

Unfortunately, you should have said "....a few MORE years to sort out the glitch."

R1200RT's much newer than your '07 have had inexplicable low-mileage FD failures already.

Problem hasn't gone away. :violin

Different "glitch" Kevin,

I believe he was talking about the clutch splines "glitch".. heck, it didn't take them more then 3-4 decades to get a good handle on that one. :bolt

[Greenwald]

Different "glitch" Kevin,

I believe he was talking about the clutch splines "glitch".. heck, it didn't take them more then 3-4 decades to get a good handle on that one. :bolt

Consider me corrected. Thanks.

Only 3-4 decades?

Damn - I won't even live long enough to see the FD failure issue actually get resolved.

Bummer. :banghead