Oil Leak... Drive Line Flex

[Bumwah]

I was checking transmission and rear end fluid levels and found residue, oil wicking on the bottom support, below the flex connector.

What I see is, a rubber boot over the u joint, with two tywraps holding it tight to the drive housing. It looks like the tywraps are starting to harden and maybe letting a bit of oil out. Any recommendations? Can I replace the tywraps? Are they SPECIAL BMW tywraps? Is there a torque spec? Am I overthinking it and just wipe it down and check fluids often? Do I need the Swami From Miami?

This is NOT a panic issue, but I'm curious... Thanx!

[dirtrider]

21 minutes ago, Bumwah said:

I was checking transmission and rear end fluid levels and found residue, oil wicking on the bottom support, below the flex connector.

What I see is, a rubber boot over the u joint, with two tywraps holding it tight to the drive housing. It looks like the tywraps are starting to harden and maybe letting a bit of oil out. Any recommendations? Can I replace the tywraps? Are they SPECIAL BMW tywraps? Is there a torque spec? Am I overthinking it and just wipe it down and check fluids often? Do I need the Swami From Miami?

This is NOT a panic issue, but I'm curious... Thanx!

 

Afternoon Bumwah

 

 

What are you working on?

 

If a BMW 1100/1150 bike then your leak is NOT at that flexible gaiter boot. That is just where you see the internal leakage appear.

 

The most common leakage from that boot area is the final drive pinion seal  leaking (located inside that boot). A little seepage over time is somewhat normal & somewhat common (especially if you are using synthetic final drive gear oil).

 

The other possible leakage place  is at the transmission rear output shaft seal then running down & to the rear then seeping out of the boot joint (not as common as a pinion seal leak but definitely possible)

 

If your final drive fluid level & transmission fluid level is staying up then probably just monitor the seep over time.

 

If you take the boot loose & can confirm that the pinion seal is the leaker then switching to conventional gear oil might stop or slow the seep/leak  due to having more seal conditioner in it.

[Bumwah]

I checked it and, let's qualify this as seepage... There's no puddle or trail of oil, so I'm going with seepage.

It is the R1150RT and all is well. As a side note...

The new battery I bought for the 1150, wasn't necessary due to the new battery charger reconditioning The old one,  so it not only fits in my '74 R90/6 but, starts fine and runs spectacularly. WIN WIN!

Thanks for the information. Great job as alwayz...

[dave_a]

When I bought my '99 R1100R the previous owner had overfilled the transmission. I found significant amounts of oil in the same place. After a refill to correct level (on the center stand) no further issue. For what its worth.

[AndyS]

Hi Bumwah.

What you have there is not unusual. It can happen through change of oil, through aggressive riding, extremes of temperature....

However, the amount of oil is very small. It will be worth a clean out of the affected area, replace the cable ties (or metal clips - dependent on what you have. I just use black cable ties). Then monitor it over the next year. You will probably forget about it.

[James in OK]

I have also found that I get more seepage with synthetic transmission/rear drive oil.  I have gone back to conventional gear oil on my last change and have less seepage now.