Rear brake pedal goes down too far.. bleeding?

beaver

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Had this from dat one... it goes about 40mm before it starts to do anything. so I adjusted the treaded U conection to bring it up.. but then the rear started to bind so had to put it back.. so I guess it needs bleeding.
I'm thinking they all go into a block under the tank (so that lot has to come off)... and I guess I bleed the pedal to block line there?.... would imagine there are 5 lines to bleed in total to do the full job... pedal and front brake being two, two to the front after the block and one to the rear.. does this sound about right... job for Sunday when it rains...
Ordered Haynes already bot still not here :(
 
Had this from dat one... it goes about 40mm before it starts to do anything. so I adjusted the treaded U conection to bring it up.. but then the rear started to bind so had to put it back.. so I guess it needs bleeding.
I'm thinking they all go into a block under the tank (so that lot has to come off)... and I guess I bleed the pedal to block line there?.... would imagine there are 5 lines to bleed in total to do the full job... pedal and front brake being two, two to the front after the block and one to the rear.. does this sound about right... job for Sunday when it rains...
Ordered Haynes already bot still not here :(

If you have ABS I believe you have to do this

 
I had a similar problem with my MY2016 GS so like you I adjusted the rear brake pedal, but mine didn't bind. my MY2018 does the same now with 600 miles on the clock so looks like I'll be adjusting it again unless as you suggest it might need bleeding so I'll be interested to hear if anyone else has experienced this and what the outcome was
 
If you have ABS I believe you have to do this


Interesting.. so he's doing the full system, but using a GS911... which I don't have?.... If there is air in the system I didn't want to push it past the block into the rest of the system as I think the rear brake is ok (but how do you tell with these linked systems??)
Mmmm... see if anyone else posts.. if not, I'll just have a play Sunday ;)
 
Interesting.. so he's doing the full system, but using a GS911... which I don't have?.... If there is air in the system I didn't want to push it past the block into the rest of the system as I think the rear brake is ok (but how do you tell with these linked systems??)
Mmmm... see if anyone else posts.. if not, I'll just have a play Sunday ;)

Better not to play with brakes..............
 
This is not an uncommon problem. I guess I have around 40mm of travel on mine, possibly more. It's been raised as an issue for the 12K service at the end of the month. Pumping the pedal makes sod all difference. richardbd of this parish tells me his EU 4 TB has been bled twice.

Update: Just measured - the tip of the lever on my bike goes down 60mm with moderate hand pressure. The brake's unusable.
 
Unfortunately without the ability to run the abs pump, bleeding of the system is virtually impossible. It’s the same on all abs bikes.

Hence the need for the GS911.


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My 2017 bike had what I thought was excessive travel, but after the recent 6000 mile service it was much improved, and back to what I would expect. Looks like they did the brake fluid replacement as scheduled for this service, which I guess would have flushed out any air in the system.
 
I did ask at my annual service (1st 12 month service) why there was a need to change the fluid. The answer I got was that it was part of the schedule from BMW. The reason I mention this is because most other manufacturers don’t change fluid until 2 or 3 years. In the car world there are manufacturers offering sealed for life on the brake fluid, which makes sense as modern fluid doesn’t go bad (unless you’re using the vehicle to race).

Makes me wonder if there is an inherent issue with the system on the BMW, especially as several have noted the increase in movement on the rear brake.

I’m also sure that someone will argue that brake fluid does go off, however when I worked in the trade we invested in an expensive piece of kit to test brake fluid. To our surprise even the crappiest looking fluid that was several years old in very old cars was still perfectly fine.


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Yes, and if BMW know that there is likely to be excessive travel from the factory then they should bleed the brakes at the 600 mile service. Maybe fluid replacement at 6000 is a requirement by Brembo to flush out any debris from initial bedding in of the internal components, or perhaps insurance by BMW against ABS unit problems.
 
Just been for a run... maybe I need to back it off more... just feeling the discs, the fronts are warm / hot as you would expect having come home and stoped.. but the rear is red hot.. far to hot for the braking iv'e done, so must be still rubbing !... so I guess by the time I've re-adjusted it I will have 50-60mm also...

As you say, pumping it does nothing.. its not a seal issue... think its more air...

but my foot is close to 45 deg before it working!... just can't be right?

I also get a grab or release (can't work out which) just before the front brakes come to a stop?... does anyone else get this?
 
I took my 2014 GS bike back to BMW and they told me they had bled the brakes, the travel was less for a few miles but eventually went back to too far travel again. Was told this is normal!
I think back brake peddle with this much travel is really not usable.
 
Just backed it off again... so its now adjusted so there is a 1mm gap between the pedal and frame as rest.. so it ensures the piston is fully home.. it does appear ok, but I'm sure when on the move or with the engine going, the problem will return (it has to, the way ive gone on the thread can only make it worst)...
I know the front brake works both, but having the rear this low makes it useless... only other option is to put a block under you boot front to level up your foot when riding... just not great when you get off LOL.. :nenau
 
Just done about 70 miles around he Dales, taking in a nice fish supper ... yum
on getting back, I can easily put my fingers on the front disc... but the rear is too hot to keep your fingers on... is this right or is it binding.
 
Just done about 70 miles around he Dales, taking in a nice fish supper ... yum
on getting back, I can easily put my fingers on the front disc... but the rear is too hot to keep your fingers on... is this right or is it binding.

binding. The discs will get hot during braking but shouldn't be hot afterwoods.
I dont think the adjuster on the brake is to adjust brake pedal travel.
 
binding. The discs will get hot during braking but shouldn't be hot afterwoods.
I dont think the adjuster on the brake is to adjust brake pedal travel.

Guess it is...so needs bleeding as there must be air keeping it in contact... Can it be done without a GS911 ?? Anyone know?
 
My 2016 TB was like that. 50mm travel before anything happened. I tried bleeding and adjusting the lever but it made sod all difference. In the end I asked the Dealer to look at it. They bled it but forgot to back the lever off so it seized solid on me 3 miles down the road :blast. Dealer came out and recovered the bike and adjusted the lever. Now the fucking brake pads wear out after 3000 miles. Planning to back the lever off again.......
 
If there is no air in the system, it could be the master cylinder seals. A trick we used to use when I worked in the trade to help diagnose faulty seals is to press the pedal slowly, see how much travel you get, then release. Give it a couple of minutes then stamp hard on the pedal. If it is firmer with less travel, it suggests the seals are worn/faulty. The reason for this is that on a slow steady press the seals ‘flow through’ the fluid. With a hard sharp press, the seals are forced against the fluid which expands the seals and they then act as they should do.

It’s not a guaranteed method, but having tried it on numerous cars and on my 2010 Speed Triple, every time it proved the master cylinder seals were faulty and on replacing the seals or master cylinder the problem was solved.


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