04 R1150RT Final Drive Rebuild Options

23217 said:

I suppose you could measure the old race, bearing, and shim and compare it to the new bearing and race and adjust for the shim. But, this alternate method might be risky.

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That's putting it mildly. The whole notion of doing that (and it's regurgitated on all forums, with everything that is shimmed) depends on it having been right to begin with. IT BROKE. Why would you want to put it back together the way it was?

2dflier said:

Well that answers that question. The only reason I could think that BMW would specify a bearing puller rather than a splitter is a concern that maybe the crown gear wouldn't be strong enough for the load required to break the bearing loose.

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You need to move the bearing about a half inch outward and you only have about a half inch of 'splitting' in which to do that. Or you have to then put it in a press or something - a secondary operation. A puller zips it off in no time flat. A puller is all I use. BMW wants their dealerships to use efficient tools. Jaws don't fit? Ummm .. you bought the wrong puller.

The backlash is usually too great on the bad FDs I receive for repair. There isn't a scenario under the sun that would let me ship a FD without checking the backlash.

23217 said:

The BMW manual states that the gear backlash needs to be checked if the tapered bearing is replaced. But, I suppose if the replacement bearing/race comes from the same lot, the size would probably be the same. I understand your position, and the existing shimming may be correct. But I think the backlash should be checked. Being wrong means that it could ruin the FD. I am always more comfortable when I know that everything is correct versus I think that it is correct.

Considering that the deep-grove bearing mfg was changed, I would expect the width of the bearing to be different. So, I don't think you can rely on the shimming of the deep-grove bearing to prove that the shimming of the tapered bearing to be correct. I suppose you could check the old and new bearing with a caliper.

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Have you compared different bearings of the same type? It never ceases to amaze me how close they are dimensionally.
All manufacturers work meet to extremely tight tolerances

The crown bearing shaft is aluminum - not hardened steel. That's probably why they don't want you to use a bearing splitter & recommend a puller instead.

Since the shaft is aluminum, you might try to chill it in a deep freeze & then quickly use the dual tire iron method to get the crown bearing off. Or if you could get some dry ice or even liquid nitrogen, chill even more and the bearing inner race should drop off with little or no effort. LN2 is surprisingly available. Use a styrofoam container.

nrpetersen said:

The crown bearing shaft is aluminum - not hardened steel. That's probably why they don't want you to use a bearing splitter & recommend a puller instead.

Since the shaft is aluminum, you might try to chill it in a deep freeze & then quickly use the dual tire iron method to get the crown bearing off. Or if you could get some dry ice or even liquid nitrogen, chill even more and the bearing inner race should drop off with little or no effort. LN2 is surprisingly available. Use a styrofoam container.

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The crown bearing shaft is steel (part of the crown gear) the shaft for the tapered bearing is aluminum.

GSAddict said:

Have you compared different bearings of the same type? It never ceases to amaze me how close they are dimensionally.
All manufacturers work meet to extremely tight tolerances

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I don't know a whole lot about bearings but work with peoples that do. From them I understand there are volumes of industry standard tolerances for every dimension and bearing class. Google tapered roller bearing tolerances and pull up Timken's 834 page tapered bearing application catalog.

If I'm reading the SKF specs correctly, the effective width tolerance associated with the SKF 30205 bearing is +0.200 / -0.000 mm (16.25 - 16.45).
http://www.skf.com/group/products/bearings-units-housings/roller-bearings/tapered-roller-bearings/single-row/index.html?prodid=1310000205

GSAddict's experience probably and reasonably suggests SKF manufacturing variation may be a whole lot tighter than this, but who knows. The original bearing was mfg in Germany. The BMW replacement I just received is stamped Mexico. Does that make a difference? Who knows, but the bearing tolerance is greater than the preload tolerance and 4 times the step in shim sizes so you have to figure something is expected to change when you replace one or both bearings.

It may be splitting hairs, but the free dimensions are only part of the equation as the mounted preload is also dependent on cup and cone fits on the shaft and in the housing, which themselves are dependent on ID and OD tolerances.

What is most daunting is all of this stack up on the tapered bearing side will be measured in a backlash spec of 0.003 - 0.006". Considering the quality of the instruments and tooling being used by novice garage hacks (me), it's hard to imagine the measurement error being much better than this. But it's easy to imagine screwing something up if the backlash isn't at least checked as best able. Too tight is probably much easier to detect than too loose, but what are the consequences of either condition?

I can't comment on Timken's specs. The BMW FD crown ring bearing is a FAG 61917 bearing. It is most likely made in China by a small number of factories around Shanghai. Like most vehicle mfg, BMW would outsource the mfg of the crown bearing to the lowest bidder. The contract winner would then sub-contract the job to a factory in China. Just because it states "Germany" or "Mexico" doesn't mean that it was really made in that country. The country name on the bearing is most likely the contractor's location. Here is a picture of a crown bearing from BMW:



I did check the width variances of the bearing and it ranged from 18.01mm to 18.19mm. So, in my opinion you can't rely on each bearing to be the same. I can't tell you the variances of the tapered bearing because I don't keep a spare. Personally, when I take a FD apart I check all the shims to see if they are within specs. The tapered bearing is the hardest to check without the proper tools or jigs.

In regards to consequences of getting it wrong. There are probably some other people who have thought about this more then I have, and may have a better answer. Or, even correct my answer. You need a minimum of 0.003" because when the metal heats up it is going to expand. Less then this, the gears will not be adequately lubricated and will wear quickly until they come into spec. I suppose if the backlash was well below zero when heated, it could crack the housing where the tapered bearing is located. Being beyond 0.006" wouldn't damage the unit. But, with mileage the backlash could become so large that it could break off a gear. As you put on more mileage the bearings and gears will naturally wear, and the backlash will obviously become higher. Getting the backlash (play) correct in the ring and pinion is not as daunting as it seems. You just have to come up with a jig that will let you measure it. I would recommend using a dial indicator versus using a feeler gauge (I am presuming that you might have considered that). I would use a magnetic base on the ring with a dial indicator and make a special piece for the center of the crown gear. Maybe use a deep well socket with a flat prong welded onto it. Or, take a piece of bar stock and drill two holes in it, and bolt it into the wheel lug nuts. Make repeated measurements until you get the consistent reading. If you cannot get consistent readings, then you will need to reconsider your jig. Once you have a good jig, then move 120 degrees around the ring and measure it again. And, finally move another 120 degrees and measure it again. Once you are done with the measurements, you will probably know if you have done it correctly.

If you don't have confidence in your measurements, you could always see if a local mechanic or machine shop can do the measurement for you. You could also take it to your local BMW dealer. A BMW shop would have the shims in stock, so this would save time. It should only take them a few minutes to do with the BMW tools. Or, you could ship it out to a number of shops around the country. It really is not as hard as it seems.

GSAddict said:

The crown bearing shaft is steel (part of the crown gear) the shaft for the tapered bearing is aluminum.

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GSAddict is right. Heating & cooling won't do anything for removing the crown bearing. I was mentally confusing the tapered roller bearing and its aluminum shaft with the crown bearing and its steel shaft.

The last of the parts showed up today. I have a dial indicator and other goodies coming in the next couple of days and may take Friday afternoon off to mess around with the measurement tooling to see what I can come up with. It's not nearly so daunting now that I know what needs to be done. It's just figuring out how get it done accurately.

If the bearing was made in China, and sold in the USA. the country of origin would have to be marked on it or the box. Anything else is a violation of the law.

I strongly suspect his bearing is made in Germany. The Chinese are too inconsistent with raw materials, heat treat and anything else quality related.

Rod

Before I respond, let me say that I don't want to get off on this thread.

If the bearing was made in China, and sold in the USA. the country of origin would have to be marked on it or the box. Anything else is a violation of the law.

I strongly suspect his bearing is made in Germany. The Chinese are too inconsistent with raw materials, heat treat and anything else quality related.

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The FTC does not require country of origin on products, with the exception of a few products. You can find those products in the 3,000 page Harmonized Tariff Schedule. The FTC does require that if you stamp "Made In USA" on your product, then "All or virtually all" of the product must be made in the USA. The requirement is self-regulating, and is usually enforced by a lawsuit from a competitor. The FTC does not regulate country of origin for companies in other countries. Those countries, like Germany, have their own laws.

If you go to the two major bearing mfg in China, you will see virtually every bearing company in the world listed as clients. This includes bearing companies in Germany and the USA. I did an extensive search on the FAG 61917 bearing a couple months ago. They seem to be the only two making this bearing. I wanted to see if I could find a higher quality bearing then what BMW was supplying. Unfortunately, what we are getting from BMW is probably the best. The FD probably should have been made with a double deep-grove bearing. In my opinion, BMW skimped on the bearing, and that caused a higher failure rate. But, the primary reason for the failure is because it is not shimmed correctly. In my opinion, the solder method seems to be working better then BMW's procedure. The secondary reason for failure is because the bearing is not strong enough.

The Chinese are capable of making any quality product requested. The customer just needs to specify the materials and how they want it made. But, unfortunately the customers primary concern is the price.

If you want to discuss this further please Email or PM me. I don't want to get off track on this thread.

23217 said:

I can't comment on Timken's specs. The BMW FD crown ring bearing is a FAG 61917 bearing. It is most likely made in China by a small number of factories around Shanghai. Like most vehicle mfg, BMW would outsource the mfg of the crown bearing to the lowest bidder. The contract winner would then sub-contract the job to a factory in China. Just because it states "Germany" or "Mexico" doesn't mean that it was really made in that country. The country name on the bearing is most likely the contractor's location. Here is a picture of a crown bearing from BMW:

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A few years ago I looked into sourcing this bearing thru local bearing houses. I once worked for a bearing house and still have good contacts. FAG Canada informed me this is a special bearing with a C3 clearance built specifically for BMW. There was no local stock in NA and min order was 25pcs stock Germany.
As far as marking goes, the country etched on it is the country of manufacture.
I have seen more than one bearing # of the same brand marked with different countries of manufacture.

When I researched it, it showed that The Schaeffler Group has the mfg done in the 15 plants in China, Korea, and India, with Shanghai being the headquarters there. They list the Deep Grove Bearings being mfg in China. This particular bearing would be MTO. Since BMW made the specs, they can have anything they want stamped on the product. I am sure BMW contracted it to Schaeffler, and they sub-contracted it through FAG Bearing China (owned by Schaeffler). The price quote I got was $0.68 USD for the bearing in quantity higher then MOQ. You can go to Schaeffler's website in China and do the same research I did. You can also go through some other bearing mfg that Schaeffler uses and buy at a lower MOQ. I am sure if you went directly to Schaeffler the MOQ would be much higher.

23217 said:

When I researched it, it showed that The Schaeffler Group has the mfg done in the 15 plants in China, Korea, and India, with Shanghai being the headquarters there. They list the Deep Grove Bearings being mfg in China. This particular bearing would be MTO. Since BMW made the specs, they can have anything they want stamped on the product. I am sure BMW contracted it to Schaeffler, and they sub-contracted it through FAG Bearing China (owned by Schaeffler). The price quote I got was $0.68 USD for the bearing in quantity higher then MOQ. You can go to Schaeffler's website in China and do the same research I did. You can also go through some other bearing mfg that Schaeffler uses and buy at a lower MOQ. I am sure if you went directly to Schaeffler the MOQ would be much higher.

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I just talked to Engineering at Schaeffler Canada and I was assured that if it said Germany on it, it was indeed made there.

One another note I own a Control Panel manufacturing business.
Most (sadly) major Control Equipment manufacturers (GE Fanuc, Rockwell, Modicon, Schnieder, Weidmuller, Wago etc.) have their product made under license in China. Every box I receive clearly shows the country of manufacture which is mostly China.

More to ponder

This is a failed 61917-C3 cut open.
The telltale of impending failure was a low level grumble when spinning wheel and silver flakes on the magnet.

I just talked to Engineering at Schaeffler Canada and I was assured that if it said Germany on it, it was indeed made there.

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See your PM.

GSAddict said:

This is a failed 61917-C3 cut open.
The telltale of impending failure was a low level grumble when spinning wheel and silver flakes on the magnet.

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I haven't seen any flakes on the magnet - just dark fines - but seeing these pics I am tempted to cut it open. But it's probably a good idea to keep it around as a spare.

Spare bearings. Do you suppose owners of other marques keep spare bearings or debate at length about such things? Do you suppose BMW does this intentionally so owners of their product aren't intimidated by the prospect of breakdowns and roadside repairs?

2dflier said:

I haven't seen any flakes on the magnet - just dark fines - but seeing these pics I am tempted to cut it open. But it's probably a good idea to keep it around as a spare.

Spare bearings. Do you suppose owners of other marques keep spare bearings or debate at length about such things? Do you suppose BMW does this intentionally so owners of their product aren't intimidated by the prospect of breakdowns and roadside repairs?

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You don't have to cut it open to see what my picture shows, you just have to look inside with a strong light source.
I just cut it open to get a good photo op.
If this happened road side I would jut turn the outer race 180 degrees and would not worry about getting home.
The grumble spinning on the center stand is very evident once the bearing gets this worn and the silver flakes are evident on the magnet.
As far BMW goes, read the other brand forums, lots of issues with those bikes too. I have 2 friends with Honda GL1800's.

OK guys, back to the basics. 02RT1150, bike on center stand. 6 and 12 oclock, 3 and 9. how much is to much, if i had to guess i have a good 16th of an inch of slack. both ways, sometimes i can feel it when riding. no metal shavings whatsoever in oil. ive had the r12c fd apart before but no experience with the rt fd. what gives here. thanks in advance.

ratze said:

OK guys, back to the basics. 02RT1150, bike on center stand. 6 and 12 oclock, 3 and 9. how much is to much, if i had to guess i have a good 16th of an inch of slack. both ways, sometimes i can feel it when riding. no metal shavings whatsoever in oil. ive had the r12c fd apart before but no experience with the rt fd. what gives here. thanks in advance.

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Seeking an answer to that question is precisely why my FD is torn down. I read answers on line from no movement at all to a little is okay. My pivot bearings are shot which would have masked any wheel movement were there any to detect. When all is said and done the crown bearing is the only one that probably doesn't need to be replaced but is going to be since it's got 84K and is staring me in the face. Unmounted both the new and old bearing have a little axial free play but if I had to guess it no more than a couple/few thousandths. Mounted and installed I'm expecting little if any movement. Where are you seeing 1/16? Are the C and RT FD that different? I didn't compare part numbers, but the parts breakdowns look identical.

2dflier said:

Seeking an answer to that question is precisely why my FD is torn down. I read answers on line from no movement at all to a little is okay. My pivot bearings are shot which would have masked any wheel movement were there any to detect. When all is said and done the crown bearing is the only one that probably doesn't need to be replaced but is going to be since it's got 84K and is staring me in the face. Unmounted both the new and old bearing have a little axial free play but if I had to guess it no more than a couple/few thousandths. Mounted and installed I'm expecting little if any movement. Where are you seeing 1/16? Are the C and RT FD that different? I didn't compare part numbers, but the parts breakdowns look identical.

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The big bearing is the same on c and rt, my rt has been that sloppy for 25k. the pivot bearings wer renewed last winter, still when checking 9 and 3 o clock or 12 and 6 there is a good 15 thousand inch. i am assuming its the big bearing, i keep an eye on the fluid for metal shavings but none thus far. but, is my crown gear and pinion gona chew themselfs up on account of big bearing slop. i have been lucky enough to get this bike from the southern tip of mexico to deadhorse ak jes this year alone. just tires,,we will be home in a week or so, looking for an older gs to restore this winter and ride it around the horn next year.