final drive bearing failure?

[seisouso]

I have an 04 with about 18000 miles on it, and I notice that there's oil/grease on my rear wheel and paralever. I wipe it off and decide to keep an eye on it. A few days later, there's quite a bit more on the rim and around the final drive bellow. I take it in to the dealership and he says after an inspection that it's not a seal problem, but a bad final drive bearing, and quotes me $700 to fix it. He says that it happens sometimes, and that BMW has since redesigned the bearing. I haven't heard of this being a common problem, and am wondering if you guys might know if this is a known problem, and if that repair quote sounds right. It kind of burns that this would have to happen six months after my warranty ended.

[def38]

I have an 04 with about 18000 miles on it, and I notice that there's oil/grease on my rear wheel and paralever. I wipe it off and decide to keep an eye on it. A few days later, there's quite a bit more on the rim and around the final drive bellow. I take it in to the dealership and he says after an inspection that it's not a seal problem, but a bad final drive bearing, and quotes me $700 to fix it. He says that it happens sometimes, and that BMW has since redesigned the bearing. I haven't heard of this being a common problem, and am wondering if you guys might know if this is a known problem, and if that repair quote sounds right. It kind of burns that this would have to happen six months after my warranty ended.

BMW changed the design of the crown wheel bearing to fewer balls. The older design with more and smaller balls would fail on some bikes. The failure mode was the cage would crack and come away and the balls would wad up all together…a massive failure requiring removal and complete disassembly of the FD, installation of a new bearing and re-shimming and adjusting lash for the gear set.

Many BMW shops do not perform this work due to lack of skill, experience, tools and gauges. Instead, they order a new FD from BMW and merely install it.

If your bike is out of warranty, order the FD and install it yourself. There are no challenging operations regarding the installation of a FD unit. Also, while you have the Paralever down, perform a spline lube.

Finally, I run 75w-140 synthetic GL-5 gear oil in my transmission and FD to which I ad 10% moly. Moly keeps seals happy, reduces friction and heat and helps the transmission shift smoothly.

[baltm604]

http://www.beemerboneyard.com

[seisouso]

Thanks for the responses. Well the $700 repair is actually less than the cost of a new final drive, so I guess I should be grateful. Besides which, I don't have a garage to work on it anyways. Luckily the bmw dealerships around here service police bikes, so the mechanics should be pretty experienced, though sometimes a bit busy. Knowing that this is a known problem actually makes me feel a bit better somehow, I guess misery loves company!

[def38]

Thanks for the responses. Well the $700 repair is actually less than the cost of a new final drive, so I guess I should be grateful. Besides which, I don't have a garage to work on it anyways. Luckily the bmw dealerships around here service police bikes, so the mechanics should be pretty experienced, though sometimes a bit busy. Knowing that this is a known problem actually makes me feel a bit better somehow, I guess misery loves company!

I would request some after warranty good will help from BMW for this failure. With your low miles and being out of warranty for only a short period, BMW may help with part of the repair. It is a well-known failure that BMW did address so, you may get some help. Can't hurt to try.

[priapismic]

I would request some after warranty good will help from BMW for this failure. With your low miles and being out of warranty for only a short period, BMW may help with part of the repair. It is a well-known failure that BMW did address so, you may get some help. Can't hurt to try.

+1 on this approach. I noticed a bit of dirty grime accumulating around my final drive in this same area. After cleaning it would recur after a hundred miles or so. So I took it to my dealer and asked that they contact BMW about a goodwill repair. Even though I was a few months past my 36 months on the warranty, I hadn't yet hit the 36k mile mark yet. I figured it didn't hurt to ask. It took a few days, but BMW agreed to pay for half the repair, which turned out to be just a leaky seal. Better than nothing. Wouldn't hurt to go ahead and ask. But don't just take your dealer's word, make them ask BMW on your behalf. They should be happy to go to bat for you. If you have to, ask for the BMW rep's name and number for the area, and contact him or her yourself.

[challey]

This topic came up at a tech seminar run by Paul Glaves at last year's international rally. The message was that the FD bearing failures have been a bit higher than expected with both the original (19 bearing?) and redesigned unit (17 bearing?).
There were 2 recommendations:
1) Change the FD fluid when you change engine oil and thoroughly check the drained gear lube for metal shavings - the fluid change won't prevent the bearing failure but it will provide you with advance notice, much better than finding out about it when you're on the road and:
2) Use conventional, not synthetic gear lube in the FD - the feeling is that the conventional lube provides more initial protection from cold than synthetic (less slippery, so more remains on the bearings) and that synthetic is really not needed because the FD does see a lot of stress and heat.

Just passing along the information. FWIW, I used Red Line 75W90 in my FD when I did my 12k service. I did an oil change a few weeks ago and also changed the FD. There was nothing alarming on the magnet or in the old fluid, so I refilled the FD with the remaining Red Line. I do plan to switch back to conventional lube when I do my next oil change - not convinced it'll help but it certainly can't hurt.

Charlie

[def38]

Failure of the crown wheel bearing in the FD is brought on by a failure of the cage which holds the balls in place. This failure can be averted by using moly to reduce friction. Reduced friction reduces heat. The cage can get very hot in local spots where balls are running against the cage itself. The cage usually cracks allowing the balls to "wad up". This is a gross failure and can be averted by friction reducing additives in the oil.

I use synthetics (75W-140 GL-5) because they do not foam, a problem with some of the high zoot oils some riders use.

[seisouso]

Wow, thanks for the advice on asking for the after warranty work. I called the shop and they said they'd contact BMW for me and try to get them to pay for it. He said he thinks there's a decent chance that they should be able to work something out. I should know tomorrow, fingers crossed!