Final drive bearing

[christianf]

I am interested in a 2004 RT but the current owner mentions having had to rebuild the final drive bearing after issues with that. Should I be concerned and what should I look for when I go to see it?

[Alba]

I rebuilt my 2002 RT final drive bearing after it failed and have had no trouble.  So as long as he used good parts and is a capable mechanic I would not see an issue almost the other way and it's a positive he told you about the rebuild.

 

What to look out for; excessive rear wheel play and/ or oil seeping on the rear wheel.

 

... only my ramblings 

[Red]

Ditto Alba,  I had a final drive bearing identified as being questionable at about 65K miles in a routine service.  I replaced it and sold the bike at 116k with absolutely no issues.

[Lowndes]

Christianf,

 

There are several bearings in the "final drive", more info on which bearing(s) was/were replaced and by whom could be helpful to you.  There is the large (+/- 5" dia) inboard "rear axle" ball bearing (closest to the wheel), the smaller outboard tapered-roller bearing (on the axle), and the two pinion shaft bearings , all in the FD.   Replacing the seals is an "easy" job but a full rebuild requires some special tools 

 

The way to check the current condition of the FD is put the bike on the center stand and 1) try to shake/move the top and bottom of the wheel left and right, use both hands and a lot of muscle.  There should be NO play.  Then, 2), still on the center stand, crank the bike and put it in maybe 3rd gear and at idle listen to the FD with the rear wheel spinning.  Use a stethoscope or a long screwdriver to listen to each bearing.  "Whirring" noises are good, loud or crunchy noises are a concern.   

 

The ring and bevel gear is a high shear mechanism that "wears out" the lube oil much faster than a spinning shaft.  There isn't much oil in the FD (8.5 oz ~ 1 cup) so changing it regularly and frequently is very important.  Fortunately its the easiest, fastest, and cheapest oil change on the bike and with no filters and no tupperware in the way.  I'll usually drop the FD oil into a water bottle with the top cut out while the engine oil is draining.  EZPZ.

[dirtrider]

20 hours ago, christianf said:

I am interested in a 2004 RT but the current owner mentions having had to rebuild the final drive bearing after issues with that. Should I be concerned and what should I look for when I go to see it?

 

Morning  christianf

 

Replacing the final drive 'crown bearing' (Deep groove bearing) was somewhat common on the BMW 1100/1150 bikes.

 

BMW changed the bearing & changed the  number of balls in the  bearing trying to offer a more robust bearing but some still failed in service.

 

In most cases the bearing wasn't the failure root, it was the ball separator inside the bearing that failed, then allowed the balls to all end up in one place.

 

As long as the crown bearing, in the bike that you are  looking at,   was replaced in a timely manner (soon after failure), so the bike wasn't ridden very long after the failure was noted, then it probably did no internal damage to the ring gear or other bearings  (I have a installed 'many' 1150 crown bearings without further problems).

 

The thing to be wary of is WHO did the final drive bearing install on that bike after failure!  This can be important as 'JUST' tossing in a new (un-shimmed)  bearing is leaving the final drive open to a future re-failure.

 

To properly install a new crown bearing the new bearing preload must be properly measured & shimmed correctly as well as the other bearings & cavities in the final drive properly cleaned of  possible failed-bearing debris.

 

If the new crown bearing was properly installed, & properly shimmed,  then I wouldn't worry about it causing any issues but if the new bearing was just installed by the last owner with no measuring or proper shimming then there is a greater chance of bearing re-failure in the future. 

 

Ask the present owner WHO did the bearing install & ask to see the receipt (if done at a repair shop).  If he did it himself then try to have him explain WHAT shimming process that he used. Also try to assess his tools, knowledge, & ability to do it correctly.

 

There are ways to properly shim the bearing if doing the bearing replacement yourself but the person doing the work really needs to understand the work-around process & what they need to accomplish with the work-around.  (just tossing is a new bearing without proper shimming  isn't acceptable)

[christianf]

Great info thank you. I will follow up with the owner. I believe that MaxBMW in CT did the work which would be reassuring. 

[Jim Moore]

I'd feel pretty good about that. If the current owner simply re-used the same shims it will probably fail again. I'd be willing to bet that Max did it right.