Link to picture- noise

[ChicotDave]

I have posted several threads trying to determine a noise from my back wheel. I eliminated brakes, tires and was finally convinced it was inside the rear housing. I removed the rear crown assembly

http://i274.photobucket.com/albums/jj278/ChicotDave/IMG_5395.jpg

When I rotate the assembly as such

http://i274.photobucket.com/albums/jj278/ChicotDave/IMG_5396.jpg

I hear a grinding noise. Without further tear down, should this rotation be smooth.

Thanks

[chrisZ]

Any grinding sounds in a bearing is not good. You've gone this far, might as well pull the bearing and inspect it, (roll the races). While in there replace the large O ring and the seal. Inspect the small bearing for any spalling of the rollers, etc.

When my rear bearing started to go bad, I had some drumming type of noise and a rhythmic vibration (the wife liked the vibes however;) ). The FD lube also had metal flakes in it and was very dark, this after 90K km.

Good luck.

[username]

i linked http://www.bmwmoa.org/forum/images/approx/editor/insertimage.gif to the photos in this posts....

http://i274.photobucket.com/albums/jj278/ChicotDave/IMG_5395.jpg

http://i274.photobucket.com/albums/jj278/ChicotDave/IMG_5396.jpg

[ChicotDave]

I followed other threads and heated unit up and cover slipped off crown unit.

A piece from the big bearing laying inside housing. No scar marks on housing so looks like all I need is a big bearing. Local dealer ( 100 miles away) wants $174 for the big bearing. Can order from BMW Chicago for $105. Looks like an easy task to swap out.




Thoughts on the 17 ball unit v the stock 19.

Thanks to all that replied over the last several weeks.

Dave

[knary]

1. Get the new bearing not the old spec bearing.
2. Be certain to re-shim the new bearing. Best guess is that the old bearing was improperly shimmed at the factory. Thus the old shimming won't work for either the old style or new (slightly thicker) style bearing.

If you can get a firm time from Chicago or live nearby, go ahead and order from them, but don't be surprised if you have to wait a long time for it to show up. If it were me, I'd get the bearing locally or from a dealer with more -ahem- predictable delivery times (e.g. Max BMW).

[ChicotDave]

Here is the pic of piece broken

[ChicotDave]

Pic does not show broken piece well. It is a half-moon shape that seperates the bearings.

[knary]

Pic does not show broken piece well. It is a half-moon shape that seperates the bearings.

That would indeed cause the final drive to be a little "rough". :ha

[ChicotDave]

I looked at other threads and very little talk about the suggestion: Be certain to re-shim the new bearing.

What does this entail?

Thanks Dave

[flars]

The bearing calls for specific preload created by shims within the FD. Unless you have the special tools needed to measure everything, you won't be able to reassemble the FD correctly, and it probably fail again - and potentially very soon. You should probably farm this task out to Anton or your (non-local) dealer. Other people have reassembled their FD without the proper shims and had them fail again within a short time.

[GSAddict]

The bearing calls for specific preload created by shims within the FD. Unless you have the special tools needed to measure everything, you won't be able to reassemble the FD correctly, and it probably fail again - and potentially very soon. You should probably farm this task out to Anton or your (non-local) dealer. Other people have reassembled their FD without the proper shims and had them fail again within a short time.

You are right about just reassembling. The first time I took it for granted that mine was correctly shimmed and just replaced the bearing.:doh The second (failure) time I checked the preload and found it to be .005" too tight.
If one is mechanically proficient, determining correct shimming is not that hard to do. You need:
1) Depth micrometer
2) 2 12" lengths 3/8" keystock
3) OE BMW cd - final drive chapter

[knary]

You are right about just reassembling. The first time I took it for granted that mine was correctly shimmed and just replaced the bearing.:doh The second (failure) time I checked the preload and found it to be .005" too tight.
If one is mechanically proficient, determining correct shimming is not that hard to do. You need:
1) Depth micrometer
2) 2 12" lengths 3/8" keystock
3) OE BMW cd - final drive chapter

I believe the new bearings from BMW are around .005" thicker than the original bearings.

[ChicotDave]

I ordered the parts from BMW Chicago but found out that it would be 3 - 4 weeks before they arrived. Cancelled and ordered from Bob's. Shipped the same day. Was going to take the advice of flars10 and have dealer install. I called dealer and asked about re-shimming and the mechanic said he never re-shims. Just place bearing in oven and assembly in freezer and plop it on.

Then re-assembly. He said much ado about shims and most of the times you can do without shims.

If they don't re-shim figure I can re-assemble myself.

Thoughts before I re-assemble.

[knary]

Thoughts before I re-assemble.

check the shimming :ha

[GSAddict]

I believe the new bearings from BMW are around .005" thicker than the original bearings.
In both my cases the bearings miked out exactly the same, which is what I would expect from any ball bearing assembly. Production would be out of control if they differed by .005", typical allowable tolerances are in the .0005" range

[knary]

In both my cases the bearings miked out exactly the same, which is what I would expect from any ball bearing assembly. Production would be out of control if they differed by .005", typical allowable tolerances are in the .0005" range

BMW has, IIRC, specced three different big bearings for our bike's final drives. The old 17 ball unit that they were built with, the briefly used 19 ball unit, and a newer 17 ball unit. The latter is a little thicker than the old 17 ball unit. FWIW, it also has a different part number.