OldSteve
Registered user
I don't know why this is such an issue on the GSs - I've not noticed it on other boxers or other makes and the front brakes, both Brembos and the current Hayes don't have the problem.
"Soggy" rear brake pedal
- Thread starter Spud
- Start date
It's something to do with the linked braking system. On my bike if I apply the rear brake after applying the front brake the free play in rear brake lever has gone.
My last two or even three 1200GS’s have developed excess travel of the rear brake pedal between services, each time they are bled a significant amount of air comes out, the brake pedal is then rock solid, but over say the next 3000 miles or so it goes soggy again.
Air gets in somewhere but my dealer doesn’t have the answer - and if BMW know they ain’t telling.
Air gets in somewhere but my dealer doesn’t have the answer - and if BMW know they ain’t telling.
It’s not just a BM problem. I had one of the first Multi 1200’s. The back brake after bleeding only lasted for about 2 weeks before the pedal would go all the way without working.
Are the braking systems on these bikes from the same source???
But why does the excess travel reach a point and not get any worse - if air was getting in, it would continue to do so until the pedal had no effect, which isn't the case.
ianm00
Registered user
I think it does continue to get worse. If I leave mine (2014 R1200 GS lC) too long the pedal travel increases to a point where the brake is not usable whilst riding the bike, and when on centre stand the brake pedal gets stopped by catching the centre stand.
I have to bleed the rear brake every so often to bring the pedal back to good operating position.
Ian
Air gets in all right, loads comes out each time I ask the dealer to fix it - they can’t work where it’s getting in - every 3000 miles or so they just bleed them again, no big deal unless I was to do a very long trip, just a bit of an irritation.
Not experiencing this at all personally but had something similar on another bike with the Brembo clutch. In that case heat was the root of the problem.
It took Brembo 3 re designs to fix it ( sound familiar ) but the fix was stiffer seals. Heat from the slave warmed the fluid to the point the seal softened and distorted enough to allow tiny amounts of air pass by with each use. Traffic made it much worse due to higher engine temps. Ducati used the same M/c but never had an issue as the crankcase ran cooler but it baffled Brembo for a while.
So I wonder if the incidence is based upon rear brake use, hence heat. I dont use my rear brake at all apart from hill starts and the % auto applied by the linked system and never had an issue. So of those getting air in the system, how much rear brake do u use ?
It took Brembo 3 re designs to fix it ( sound familiar ) but the fix was stiffer seals. Heat from the slave warmed the fluid to the point the seal softened and distorted enough to allow tiny amounts of air pass by with each use. Traffic made it much worse due to higher engine temps. Ducati used the same M/c but never had an issue as the crankcase ran cooler but it baffled Brembo for a while.
So I wonder if the incidence is based upon rear brake use, hence heat. I dont use my rear brake at all apart from hill starts and the % auto applied by the linked system and never had an issue. So of those getting air in the system, how much rear brake do u use ?
chris moore
Registered user
Don’t use mine at all other than the fact that they’re linked, when it had a fluid change at service it was improved but when I bled it last week no air bubbles present and no improvement in pedal travel
Why doesn't the R1200R LC suffer from the brake pedal travel problem? My R has a pedal that has almost no travel. My GS has had stupid amounts of travel in the pedal, to the extent it was almost impossible to use.
Use mine back brake all the time on my r1200gs enduro now done 36000 miles brake pedal as always been fine
I have a suspicion that it’s heat related, the catalytic converted is pretty close to the master cylinder.
What year is your GS?
I fitted Akra decat headers less than a 1000 miles ago, so when I can get to do the service it might have solved the problem.
Any body having the same back brake problem, that are already running with decat headers?
Yup, same thing on two GSs, both with full systems.
I don't think it is to do with heat or air in the system as the brake is not spongey, it just takes a lot of travel to take up the slack in the valving in the linked braking/abs module. If you apply the front brake first then the rear you can feel the difference with reduced rear lever travel. It's just another one of the GSs quirks.
1200 or 1250 ?
Its a 2013 one of the first which didnt need the extra locking ring at the top of the forks
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