Brake Failure

Shagley

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I have a 2009 F800GS, with ABS, which was bought from new in June which only has 3000 kms on the clock. Recently the brakes seem to be "failing". This "failure" ranges from shuddering at low speed, lack of power when pulling the brake lever etc.
I have checked that the brakes calipers are not loose and that there is no liquid on the brake disks but all looks OK.
I have called the BMW dealership I bought it from and the bike is booked it to be looked at but I was just wondering if anyone else has had a similar issue
 
I find after the last two services the brakes have I feel improved in their performance. Been no real issues it's just the "after" version with fresh fluid and bled etc seems to have much more bite. But then as there's only one disc at the front on my 650 twin ...
 
Are you not describing the ABS kicking in??? I've had a moment or two going around a well known corner of mine & finding a parked vehicle where there usually isn't. Applying the front-brake it came on then suddenly 'let go' so i had 2 options. Slide my bike into the back of van or scary overtake with added wince (inside my helmet).

The ABS stops you from locking up, i now always go along occasionally squeezing my front brake to keep it warm while powering along.

Any good Shagley? :eek
 
The brakes don't feel as 'sharp' as many bikes IMO, maybe it's just that and not a problem as such.

As for the 'shuddering' - I'm with Zen on this....ABS? The back brake ABS can be a little prone to kicking in early. Having said that, I really have to slam on hard to get the front ABS to kick in.
 
A couple of things from me ...

I've had moments with my front brake where for a second or so the lever just doesn't feel 'right' ... Usually there's a fair bit of lever travel before the brake starts to bite, but on occasions it feels like that spare travel's gone and the lever action is quite stiff - almost like the brake fluid has become super viscous. Once the lever's been actuated though the 'feel' and brake performance returns to normal... Before anyone chirps in - I know what a spongy system feels like and it's nothing similar to what I'm feeling - I do wonder whether it's an ABS glitch sometimes...

The other thing ... I rode a friends 1200 the other day - a non-servo model - and was surprised by the bite and ferocity of the brake... it makes the 800's seem very tame by comparison ...

Greg
 
Thanks for the replies but I dont think it is normal activity of the ABS (even though I have never had a bike with ABS).
On Monday I was riding to work on was slowing down as I came up to some traffic lights and applied the front brake and it was at this point, for only a split second, that it just did not work!!!:nenau Once I let go and reapply it works like a charm:clap The rest of the ride was trouble free.
Perhaps I am getting a bit paranoid but I am beginning to think about it more the more I ride
Anyway the bike is booked in for Thursday so if they find anything will let you know
 
I have to say I'm not desperately happy with the fact that my brakes aren't 100% consistent ... In my book the brakes should work properly every time and I'm pretty sure an MOT tester would have something to say if the brakes 'occasionally' played up ...

So far I've just lived with it, but I'll definitely take it up with CW when it goes in for the 12k service in a couple of weeks...

G
 
Have you checked to see if the pistons in the calipers are moving freely? If one of the pistons was sticking would it cause the vibration you talk about?:nenau
 
Just one of the reasons I don't have ABS fitted ;)

:beerjug:









:hide
 
Warped disk

Has the dealer checked the trueness of the disks? I have a 2008 F650 (twin) with ABS. My dealer confirmed that my third (:eek:) front disk (F650 only has a single disk) has warped (out by 0.5mm). It feels like a vibration at low speeds and a general lack of positive lever feedback at higher speeds; not good. Thankfully Rainbow are a great dealership and are going to order in a replacement front wheel & disk under warranty. The thought is that the disk mounting points may be out of alignment. (Or perhaps the single disk is not up to the job and / or the quality of the metal may not be suitable, time will tell).
 
Well I took the bike in on Thursday into the BMW dealer I bought it from.
They said that the braking problem may be related to the fact that I had adjusted the brake lever to bring it closer to the handle bars (as detailed in the bikes manual):blast
In the end they bled the brakes and adjusted the brake lever and the brakes were instantly more responsive. Brakes were fine on the way home and today on the way to work so hopefully problem gone and my confidence levels are back up!! :thumb2
 
IThis "failure" ranges from shuddering at low speed, lack of power when pulling the brake lever etc.

It does sound *a bit* like the ABS kicking in, which is a common complaint amongst F800GS owners. ABS seems to jump in too often.

The ABS will give rapid juddering through the brake lever and a feeling that there is a lack of power in the brakes. The bike overruns your braking estimate and you often overshoot the lines on the road. My bike seems to do this less now, but when new, it was once a week at least.

There are a few threads about this on the site.

Nevertheless, sounds like it should be checked out.
 
Has the dealer checked the trueness of the disks? I have a 2008 F650 (twin) with ABS. My dealer confirmed that my third (:eek:) front disk (F650 only has a single disk) has warped (out by 0.5mm). It feels like a vibration at low speeds and a general lack of positive lever feedback at higher speeds; not good. Thankfully Rainbow are a great dealership and are going to order in a replacement front wheel & disk under warranty. The thought is that the disk mounting points may be out of alignment. (Or perhaps the single disk is not up to the job and / or the quality of the metal may not be suitable, time will tell).

I am on the 800gs(ABS, and yes I have activate it on both wheel many time so I know what it feels like), about to get both my front discs replaced under warranty due to warp. Put the discs through a creek, well a large puddle really (BMW called this normal use for this kind of bike).

Rapid cooling of metal changes it strength/density of metal thus you end up with 'hard' spots in the disc rotor, as a result they warp or feel warped.

I notice under slow speed breaking, while holding constant pressure on the leaver that the break leaver will actually move in/out a 'large' amount corresponding to the feel of no brake/braking. At high speed this feels like a horrible, incredibly strong shudder.

It really does ruin my confidence in braking especially at low speed as the brake in constantly active/inactive even with constant pressure on the leaver.
 
Just started to experience a problem with my front brake (just had its 600 mile service). Slowly coming to a halt and go to press front break. but leaver stiff and resists. Let go and try again and its fine. This has now happened at the begining of three different journeys. I think another trip to the dealers is called for
 
Well I took the bike in on Thursday into the BMW dealer I bought it from.
They said that the braking problem may be related to the fact that I had adjusted the brake lever to bring it closer to the handle bars (as detailed in the bikes manual):blast
In the end they bled the brakes and adjusted the brake lever and the brakes were instantly more responsive. Brakes were fine on the way home and today on the way to work so hopefully problem gone and my confidence levels are back up!! :thumb2

I have adjusted my lever in the same manner as you and I must admit that that my brakes now dont react as they used to, they work and eventually stop the bike but i dont get the juddering feeling:nenau
since adjusting the lever there is difference for the worse.
gonna put the lever back to the original position this afternoon and try it out.
 
I dont know anything about your bikes, but if this is mostly happening at the start of a trip or when brakes are cold could it be that there is HH pads fitted? It would tie in with the weather getting colder as these pads need heat to work. I have them on my old TDM and they are frightening when cold or very wet. Symptoms are brake judder and no real brake effect then as they warm you start to slow. Just a thought and I am probably babbling but thought I would pitch in anyway.
 
Just started to experience a problem with my front brake (just had its 600 mile service). Slowly coming to a halt and go to press front break. but leaver stiff and resists. Let go and try again and its fine. This has now happened at the begining of three different journeys. I think another trip to the dealers is called for

Sounds just like my issue too...

G
 
I've felt differences

Out for a day of riding with some friends. One on a the same F800GS but with a different sprocket, so I gave his a go. The brakes between his and mine felt VERY different. His were very touchy to me and he said mine felt mushy.
 


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