Rear brake lever 'sticky piston' problem

[Amir]

Hi,

I've just had a puncture fixed on my F650GS. When I picked it up after riding 200 yards I suddently realized I need to push the rear brake lever all the way down for the brake to engage at all. So much down that it effectively disables the rear brake.

I turned back to the shop and they informed me that this is the infamous 'sticky piston' problem with the model, which there was an 'unofficial recall' for a couple of years back, but now BMW no longer fix it for free. They said it's not their fault, and that the master cylinder needs to be replaced.

So my questions are:
1) Is this really the solution, or is there is a simpler solution ?
2) If indeed something's broken, is it their fault or not ?

Thanks.

 

[Amir]

Reading about the 'sticky piston' problem I realize this is not the problem that I have now. My problem seems to be that the piston in the master cylinder isn't fully retracted (or whatever you call the thingy in the master cylinder that the pedal pushes).

Sigh... Japs & Germans first thing monday morning. The plans for the weekend ride are off.

 

[Amir]

Problem solved.

The problem was the ABS (again). You have to treat it like you are bleeding the brakes - disengage the ABS and pump the brake lever very slowly.

 

[talltony]

You should always pump the brake pedal/lever after replacing the wheel to bring the pads out to their working position as they get pushed into the caliper as the disc is removed and replaced.This applies to either brake and regardless of whether ABS is fitted.The garage should have known this........
Tony