BMW R1200RT/R1250RT Forum

My 2006 RT seems to have developed a fluid leak. It's coming from a breather pipe which sits above my side stand. I first noticed it today when parked up for lunch. A small pool of fluid developed and then stopped. I checked a couple of times on the way back, but nothing. Once the bike was parked up at home I noticed the leak again (see photo's). It had a full service a couple of weeks back when al the fluids were changes. Any ideas as to what's going on here?

Is it hydraulic fluid.  If it is check your clutch fluid reservoir.  If it's oil it's probably a shaft seal on the gearbox.

I thought the breather tube came from air box

RTman10 wrote: Is it hydraulic fluid.  If it is check your clutch fluid reservoir.  If it's oil it's probably a shaft seal on the gearbox.

Certainly does not smell of oil and is not hot to touch so I'm thinking hydraulic fluid. But why would this come down a breather pipe?

Are you sure it's coming through the pipe and not just down it. 


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RTman10 wrote: Are you sure it's coming through the pipe and not just down it. 


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Good question, will have a closure look tomorrow. So if fluid and not oil what's around that area which could cause this?

UKDucatiman wrote:Any ideas as to what's going on here?

There's a very good chance the leak from the breather pipe is brake fluid, which was changed at the service.

I replaced the front brake pads on a 2005 RT, pushing the caliper pistons back resulted in a fluid leak near the centre stand on the bike.
On contacting a BMW Dealer, I was reassured that all is OK & that there is a vent/breather on the ABS/Servo Unit under the fuel tank.



In the photo, the Front & Rear Brake Wheel Cylinders each have a vent/breather connected to a common pipe via a "Y" piece.

The bike has servo but not abs

Does the fluid feel greasy to the touch.

Didn't know they had ever made a 1200RT with no ABS.  Nearly sure it's a standard fitting.


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I've just had some feedback from the tech who serviced the bike. Apparently this is just the fluid levels settling down post service. As the fluid expands when hot, its just venting some of it. So DaygoDavid you were spot on : )


It's funny how the mind works, I was already convincing myself it was a servo failure, with the associated massive replacement / repair costs  :not: 

So the RT is like a car and only has one fluid reservoir, which is unlike any other bike I've owned. Are the brakes then linked and do both brakes operated even if you only engage either brake on its own?

No, there are two, the rear brake reservoir is hidden behind a panel aft of the engine.

On a 2006 bike the brakes are connected to an electo servo.  There are of course still two resovours.  All RTs have semi links brakes controlled by the ABS electronics.  Hand lever will put on both brakes but if you just use the foot pedal only the rear works.  Downside to that is rear pads have a very short life span. 
As I believe the BMW boffins know how to balance the brakes better than I will ever manage to do I have just about forgotten where the foot lever is.

RTman10 wrote: On a 2006 bike the brakes are connected to an electo servo.  There are of course still two resovours.  All RTs have semi links brakes controlled by the ABS electronics.  Hand lever will put on both brakes but if you just use the foot pedal only the rear works.  Downside to that is rear pads have a very short life span. 
As I believe the BMW boffins know how to balance the brakes better than I will ever manage to do I have just about forgotten where the foot lever is.

That explains why my rear brake pads were 90% worn and the front only 60%. Replaced them both anyway but at least I now know why : )