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Discussion Starter #1 (Edited)
For those who maybe interested, here is the method I have used to compare results from Dman's dial indicator method of setting up a final drive to the depth micrometer method described in the BMW service manual.

The service manual requires a special tool to stabilize the crown wheel bearing.
In this method three measurements are taken.

Measurement "a" is the distance from the final drive cover mating surface to the bearing seat in the cover. This dimension cannot be taken directly, but is calculated by subtracting two separate measurements using a machinist's block.

Measurement "b" is the distance from the outer race of the crownwheel bearing and the final drive housing cover mating surface.

Measurement "b" is subtracted from "a" and then the preload amount of 0.05-0.10mm is added to the result to obtain the total shim thickess.

I took a final drive cover and cut it into a couple of segments that can be used as a "special tool" to stabilize the crownwheel bearing. I have learned that it is necessary to measure at two opposite points on the bearing because the bearing can be canted slightly resulting resulting in an erroneous measurement. The bearing needs to be adjusted using the special tool to ensure that identical measurements are obtained at opposite sides of the bearing.

Done carefully, this method yields results comparable to the dial indictor method introducted to this group by Dman and shown in my video.

I've never seen or used the BMW special tool but here's a diagram of it:


My homebrew special tool:


Taking measurment "b":


Taking one of two readings to get Measurement "a":


The other method, Dman's dial indicator method setup:
 

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Wrencher Extraordinaire
2005 K1200LT
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Great Pic's Curtis. It looks like you have some shim material in photo #2, is that the case? I have a spare housing now and was comtemplating a cut up of it like you did.
 

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Discussion Starter #3
jzeiler said:
Great Pic's Curtis. It looks like you have some shim material in photo #2, is that the case? I have a spare housing now and was comtemplating a cut up of it like you did.
Good catch, John. I thought you might note that. I took a 1.00mm shim and cut it to fit under the cover sections. I did this so that the cover sections would put a little downward pressure on the bearing. I tighten the cover bolts only finger tight, just enough to ensure that the assembly is fully seated and the axial play in the bearing is taken up.

I've used the setup both with and without the shim pieces in there, seems to work more consistently with them in.

When I first started using this method, it wouldn't always agree with Dman's dial indicator method. Then I realized the the bearing can be canted even with the cover sections tighened down. Now I make two measurements on opposite sides of the bearing and make sure they are the same. This sometimes requires loosening one bolt and tightening the other; again only using finger tightness. Once I get the two opposite side measurements the same I use that value. When I have done this, the two methods agree quite closely.
 

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CharlieVT said:
Good catch, John. I thought you might note that. I took a 1.00mm shim and cut it to fit under the cover sections. I did this so that the cover sections would put a little downward pressure on the bearing. I tighten the cover bolts only finger tight, just enough to ensure that the assembly is fully seated and the axial play in the bearing is taken up.

I've used the setup both with and without the shim pieces in there, seems to work more consistently with them in.

When I first started using this method, it wouldn't always agree with Dman's dial indicator method. Then I realized the the bearing can be canted even with the cover sections tighened down. Now I make two measurements on opposite sides of the bearing and make sure they are the same. This sometimes requires loosening one bolt and tightening the other; again only using finger tightness. Once I get the two opposite side measurements the same I use that value. When I have done this, the two methods agree quite closely.
Thanks for posting the pics. I think I will make a tool much like the BMW tool but make the holes countersunk and windows cut for multiple measurements. This would allow for the depth micrometer to be used without fussing around the bolt pattern.
 

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Charlie,
I have read most of your posts and watched your FD repair video. I have a 2001 1100s (ABS) model. It has a similar FD as the 1999-2004 K1200LT. The impulse sending wheel on the crown gear is loose. My speedo is erratic, so I pulled the speed sensor from the top of the FD. I can spin the impulse sending wheel with a punch while holding the rear wheel. I don't see the impulse sending wheel in the official BMW Repair Manual. It shows the crown wheel/spacer/tapered roller bearing and race. Here is the parts fiche that shows the part.

http://www.ascycles.com/Illustrated...indName=DIFFERENTIAL_GEAR_SET&bindCat=33_0640

How is the impulse sending wheel replaced? How is it attached (interference fit?). Do I have to remove/replace the tapered roller bearing and race? If so, will I have to also check the shimming of the bevel pinion and crown wheel?

Should I take it to BMW?

Thanks in advance.
 

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Discussion Starter #6
bobmwmz said:
Charlie,
I have read most of your posts and watched your FD repair video. I have a 2001 1100s (ABS) model. It has a similar FD as the 1999-2004 K1200LT. The impulse sending wheel on the crown gear is loose. My speedo is erratic, so I pulled the speed sensor from the top of the FD. I can spin the impulse sending wheel with a punch while holding the rear wheel. I don't see the impulse sending wheel in the official BMW Repair Manual. It shows the crown wheel/spacer/tapered roller bearing and race. Here is the parts fiche that shows the part.

http://www.ascycles.com/Illustrated...indName=DIFFERENTIAL_GEAR_SET&bindCat=33_0640

How is the impulse sending wheel replaced? How is it attached (interference fit?). Do I have to remove/replace the tapered roller bearing and race? If so, will I have to also check the shimming of the bevel pinion and crown wheel?

Should I take it to BMW?

Thanks in advance.
The sending ring is present or absent on various BMW models and year groups. I am most familiar with the KLT final drive and the sending ring exists on final drives up to 2002 at which time the speedometer sensor was incorporated into the ABS sensor.

The only times I have seen or heard of the sending ring becoming loose the underlying cause was the "creeping" input pinion inner needle bearing race. In any case you want to open the drive and inspect.
Open and inspect is pretty easy, you will not have to remove the tapered roller bearing or the input pinion assembly. I suggest removing the drive from the bike, removing the cover of the drive and taking a few pics and post 'em here. That'll give us an idea what you are up against.

How many miles on your bike?

Pics attached to give you an idea of what has happened on some LTs that caused the sending ring ("impulse sending wheel" on the BMW parts fische) to get knocked off its seat. (it is an interference fit).

Damage to internal housing next to sending ring:


Needle bearing race before pressed back on the shaft:


Needle bearig race after pressed back onto the shaft:
 

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Thanks Charlie for the quick response. I'll pull the final drive off the bike and take it apart in the next few days. I'll post picks of what I find. The bike has 47k on it. I change the final drive oil every year when I change the transmission oil. The magnetic drain plug doesn't have any metal on it, just a sludgy paste. I have zero play at the rear wheel when held at the 3 and 9 o'clock position. I replaced the pivot bearings last year. I do have very little play when the wheel is held at 12 and 6 o'clock. It not real noticeable.
Thanks again.
 

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Discussion Starter #8
bobmwmz said:
Thanks Charlie for the quick response. I'll pull the final drive off the bike and take it apart in the next few days. I'll post picks of what I find. The bike has 47k on it. I change the final drive oil every year when I change the transmission oil. The magnetic drain plug doesn't have any metal on it, just a sludgy paste. I have zero play at the rear wheel when held at the 3 and 9 o'clock position. I replaced the pivot bearings last year. I do have very little play when the wheel is held at 12 and 6 o'clock. It not real noticeable.
Thanks again.
Wheel wobble won't tell you anything about the final drive. By all accounts, by the time you can feel wheel wobble secondary to the final drive failing, the lube is already leaking out of the FD.

If your FD is experiencing a failure related to the tapered roller bearing on its seat, or the input pinion needle bearing problem I posted pics of above, there will not be significant ferrous metal on the drain plug magnet like there is with the "classic" crownwheel bearing failure. The input pinion needle bearing issue will put fine aluminum into the lube and your lube will be dark. Because it is mostly aluminum that is being worn, you won't see the shiney metal flakes on the magnet which is characteristic of the crownwheel bearing failure.

Has you FD lube been kind of dark at changes?

I'm betting something is wrong in the vicinity of the sending ring, most likely the pinion needle bearing race. If that is the case, a possible fix it to press the race back home (requires disassembly of the input pinion which is not for the faint of heart and requires special tools) which makes the drive good for another 47K miles.
 

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I use Red Line Heavy Shockproof gear oil in the trans and FD. It is red. When I drain it it looks more gray.
 

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Discussion Starter #10
bobmwmz said:
I use Red Line Heavy Shockproof gear oil in the trans and FD. It is red. When I drain it it looks more gray.
Yeah, I'll bet you're shedding aluminum inside the housing.
Take it apart and take pics.
We'd be happy to see what you find and that'll give evidence on what to suggest.
 

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Pointless question. Why is it you do this, when BMW won't, or didn't.
 

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"Yeah, I'll bet you're shedding aluminum inside the housing.
Take it apart and take pics.
We'd be happy to see what you find and that'll give evidence on what to suggest."

Charlie.
Here are some pics of my FD. The 1st pic shows the sending wheel. You can see that it isn't seated. I can pull it off its seat and spin/wobble it around. The races and bearing don't look damaged. The only damage I see is a small nick by the oil hole that goes to the pinion needle bearing. I'm guessing that's from the sending wheel wobbling and scraping the area. I don't feel any play or roughness when I turn or push on the pinion gear. All the bearing races look good. No pitting or scaling. The crown gear assembly turns smoothly also with no roughness or play. Could the sending wheel just come off without any other problem?
Thanks
 

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Discussion Starter #17
bobmwmz said:
"Yeah, I'll bet you're shedding aluminum inside the housing.
Take it apart and take pics.
We'd be happy to see what you find and that'll give evidence on what to suggest."

Charlie.
Here are some pics of my FD. The 1st pic shows the sending wheel. You can see that it isn't seated. I can pull it off its seat and spin/wobble it around. The races and bearing don't look damaged. The only damage I see is a small nick by the oil hole that goes to the pinion needle bearing. I'm guessing that's from the sending wheel wobbling and scraping the area. I don't feel any play or roughness when I turn or push on the pinion gear. All the bearing races look good. No pitting or scaling. The crown gear assembly turns smoothly also with no roughness or play. Could the sending wheel just come off without any other problem?
Thanks
Nothing is jumping out at me so far. I suppose the sending wheel could come off spontaneously but seems unlikely to me. I wonder if you can post these views with a little better lighting and focus. I frequently use a pocket camera but it has a close up button and I turn off the flash and use other lighting. If your camera will allow close up or macro mode, and allow you to surpress flash, do that, give it a try. I suspect you have early stage "creeping" needle bearing race; not sure it had anything to do with the displacement of the sending ring though. These are the views I'm interested in:





Thanks,
 

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Charlie,
I'll try again in the morning. I'm at work tonight. You want a better pic of the 2 you posted in your last post correct? If there is other angles you would like to see, I'll try.
 

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Discussion Starter #19 (Edited)
bobmwmz said:
Charlie,
I'll try again in the morning. I'm at work tonight. You want a better pic of the 2 you posted in your last post correct? If there is other angles you would like to see, I'll try.
I'm trying to see if the needle bearing race "a" is rubbing on the inner surface of the housing "b". I don't think it is a cause of your loose sending ring but it looks to me like there might be no space between the end of the bearing race and the housing aluminum. There should be some space there. If the bearing race is rubbing, in addition to a lack of space the race will have very fine scoring from wearing on on the aluminum housing; that's why I wanted to see a sharply focused pic.


You can also tell if the needle bearing race has creep off its seat by looking into the gap between the pinion gear and the housing. The correct viewing angle (which is narrow) and good lighting will allow you to see if there is a gap between the race and its seat on the pinion shaft. The arrow in this pic shows the gap I am referring to:


If the needle bearing is creeping, I'd disassemble the input pinion and press the race fully back on.

If you can get the sending ring back onto its seat without removing the tapered roller bearing, that's what I'd do. If not, you'll probably end up replacing the tapered roller bearing. I've not been able to remove the tapered roller bearing without stress or damage to it. If you replace the tapered roller bearing, the gear lash should be checked.
BTW I can't conclude from you pics that there isn't some scoring on the rollers of the tapered roller bearing. If there is even surface scoring, I'd replace the bearing.

And while you're in there, I'd replace the crownwheel bearing and measure it for proper preload shim thickness. Too many of these FDs have crownwheel bearing problems, you have almost 50Kmiles and replacing the bearing is relatively cheap insurance. BTW, the experience of cutting open many crownwheel bearings that felt fine but were found to have varying stages of wear/damage tells me you simply cannot tell if the crownwheel bearing is okay by the feel of it.
HTH
BTW if you don't find a cause of the displaced sending ring, I'd suggest degreasing it and its seat really well and putting a little red Locktite on before pressing it back on.
 

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Thanks for all the info Charlie. I'll get the pics to you in the morning. I'm no photographer, but I'll do what I can. I do plan on replacing the Crown bearing. If I have to also pull the pinion gear and bearing, I may try that myself also. The local BMW shop quoted up to 6.5hrs at 98.00/hr.. I can buy or fab allot of special tools for that labor charge. If I decide not to do it, there is an independent shop here that used to be BMW of FT. Worth (now Perry's Motorcycles and Sidecars). Perry has a ton of experience and will let me bring in just the final drive (not the whole bike). But the process doesn't look too difficult if you take your time and measure and it would be real satisfying to do it myself. I was thinking of the Locktite idea also for the speed wheel.
Thanks again for all your time.
 
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