Is my final drive doomed??????????

[cali_beemer]

So, I put the bike on the lift. I noticed something that didnt seem right. There was some oil and grime built up under my final drive. It looks like its been seeping out the rubber boots. This is a new to me bike that I just bought about 1500 miles ago. There is no play that I can feel at the rear wheel. I checked that before I bought it and the same was true tonight. There is some grime on the wheel as well. I havent changed the fluid yet to check for particles but that may happen tommorow. The pics are bad from nighttime amd an iphone but heres what I have. Any help please.....

 

 

[Satguy]

Probably nothing serious.

 

Check for play by holding the wheel at 12 and 6 o'clock and then at 3 and 9 o'clock positions. Try to move the wheel forward and back.... I'm not describing it very well, but you want to check the large bearing for play. Drain the oil and look for metal shavings etc. There will be some dark coloured very fine particles on the magnet.... that is normal.

 

From your pix. it appears that you have a leaking pinion seal, which is very common on BMW final drives. Cut the large tyrap and pull back the rubber boot. You will likely see some oil in that area.

 

You need to remove the final drive from the bike and have a new seal installed on the pinion side. (input side) of the drive. Probably a dealer item, unless you have special tools for it.

 

Not a huge deal unless there is side to side movement at the wheel.

 

Good Luck

[cali_beemer]

Probably nothing serious.

 

Check for play by holding the wheel at 12 and 6 o'clock and then at 3 and 9 o'clock positions. Try to move the wheel forward and back.... I'm not describing it very well, but you want to check the large bearing for play. Drain the oil and look for metal shavings etc. There will be some dark coloured very fine particles on the magnet.... that is normal.

 

From your pix. it appears that you have a leaking pinion seal, which is very common on BMW final drives. Cut the large tyrap and pull back the rubber boot. You will likely see some oil in that area.

 

You need to remove the final drive from the bike and have a new seal installed on the pinion side. (input side) of the drive. Probably a dealer item, unless you have special tools for it.

 

Not a huge deal unless there is side to side movement at the wheel.

 

Good Luck

 

Thanks. I wasnt sure if changing that seal would be a home job or not. I looked in the clymer and it appears several special tools are used. I can make those tools myself but it may just be cheaper to take the final drive off and take it to the dealer. I will clean it and keep an eye on it. I have heard that just overfilling the FD can do this. So, I want to clean it and change the fluid before considering any seal replacements. There is no play at all on the FD so I am not concerned about the main bearing being bad.

[Dennis Andress]

That oil could also come from the tranny output shaft seal. Which can also be caused by too much oil in the tranny.

 

I'd pull the boot back and clean as much oil as possible out of the swingarm and boot. Changing the tranny and final drive oils to make sure the levels are right would be a good idea.

 

Keep an eye on it and take care of it if it continues to leak. The driveshaft is rubber isolated. Gear oil will attack the rubber, causing it to swell and change the shape of the driveshaft. On early K100s a leaking tranny seal would cause the shaft would lengthen to the point that the u-joint would be damaged as the swingarm traveled up.

[Francis]

Looks like what I had on my RT. It was a seal I had the dealer fix it. Ran about $ 375.00.

[cali_beemer]

Looks like what I had on my RT. It was a seal I had the dealer fix it. Ran about $ 375.00.

 

My whole final drive fix with new bearing ran 400 at the dealer. I sure hope they dont want 400 for the pinion seal.