Brake Failure - any ideas?

[Dan79]

Hi there.....

Yet another fault with my 'pride and joy' - yesterday the brake failure light started flashing rapidly...checking the front brake i discovered it wasnt working. The brake lever doesnt 'feel' any different to normal, and the pads are touching the discs OK when pressure applied to the lever (enough to hold the bike still on a 10% gradient anyway).

Anyone else had a brake failure expreience & able to shed any light on qwhat might be causing this?

My (not) very helpful BMW dealer was closed for a stocktake today, managed to speak to them but they won't be able to help until the middle of next week.

Cheers & happy new year to everyone!

 

[pedmo]

Check the hand gaurd is not touching the brake lever at all. It can twist round and cause the brake system to think there is a fault if it touches the lever. Very common I think.

 

[Wapping]

Check the hand gaurd is not touching the brake lever at all. It can twist round and cause the brake system to think there is a fault if it touches the lever. Very common I think.

Good place to start

Have a look if the brake light is on, gives a god clue, as the pressure is sometimes just enough to activate the switch. Also check the switch for the rear brake.

 

[Dan79]

cheers for the suggestions guys. Checked position of handguard and operation of brake light - both OK. Not getting the usual whirring noise from the braking system so i am guessing there is a fault with the hydraulic pump? Bike is now out of warranty as well, so am expecting a large repair bill...

 

[pedmo]

With luck t might not be expensive Dan. I think if there is any significant fault identified during the start up checks, the system reverts to residual braking mode so the servos don't operate and make that noise. So it could be something else (hopefully not as expensive) in the system. The BWM diagnostic kit or Steptoe may identify the fault.

 

[Arthurwg]

My "brake failure(s)" required the replacement of the entire wiring harness at 3000 miles. That was under warranty, thank goodness, or it would have cost $1200. The servo system is crap, let's face it. But I haven't had a problem since.

 

[Alexd]

I've had this a couple of times, especially on cold days during this winter. Apparently the bikes "brain" shuts everything down to get the most from the battery to start the engine. That might include the ABS... Running the engine to get some juice back into the battery, switch off and restart a few mins later and the problem disappears.

Starting the bike holding the brakes or having an Autocom hard wired that reduces the battery from a full charge can create the same efect.

 

[Dan79]

thanks for all the replies guys. my dealer is collecting the bike tomorrow, hopefully it wont be too expensive to fix!

 

[Paul Mac]

Dan - can you let us know the outcome of this please.

Regards Paul Mac

 

[Brian ROSEN]

"brake failure'

I suspect it was simply a low battery - but please let us know. I have had this same problem but a quick charge has cured it;

 

[Slowly]

handgarued yep thats what caused my lights to flash just moved it a bit and tighten u

Hi there.....

Yet another fault with my 'pride and joy' - yesterday the brake failure light started flashing rapidly...checking the front brake i discovered it wasnt working. The brake lever doesnt 'feel' any different to normal, and the pads are touching the discs OK when pressure applied to the lever (enough to hold the bike still on a 10% gradient anyway).

Anyone else had a brake failure expreience & able to shed any light on qwhat might be causing this?

My (not) very helpful BMW dealer was closed for a stocktake today, managed to speak to them but they won't be able to help until the middle of next week.

Cheers & happy new year to everyone!

check hand gaerd is not in way of brake lever travel

 

[NeverRodeBefore]

Dan79 - had exactly the same thing on mine. Riding along, came to apply the brakes and virtually nothing. No noise from the servo pumps when you apply even the slightest pressure to the levers. I turned off the bike, left if for a few mins, then tried again, with exactly the same result. I had done over 350 miles the weekend before and was on my way to Alan Jeffires to look at the enduro helemts.

I rode it very carefully the rest of the way, and just walked in, the parts man checked the start-up and hand guards (already checked myself), then the mechanics reckoned the battery was low, so fast charged it, and then plugged it into their diagnostics, which after about an hour told them the servo valve (?) had blown, sending virtually nothing to the front, and 10 times normal pressure to the rear. I was offered a lone bike, but got my Dad to collect me instead, about three days or so later it was fixed.

Having recently spoken to the guy from Motorrad Services, he said that a lot of early pumps had failed, and were replaced with a newer design, so hopefully mine should be ok?

 

[aspad]

Almost certainly something to do with the servo activation switch if my experience is anything to go by. I had an intermittent recurring fault with the front lever similar to the one you describe - always evident during/after offroading.
Eventually my dealer fixed the problem - said that the servo activation switch in the front lever was not installed perfectly (somehow prone to movement/misalignment during shaking).
The back brake can also trigger the default (non servo) mode. So make sure they check the contact on that too.

 

[Brian ROSEN]

No ABS/ no servo

I thought a top up charge had cured this but it hasn't. Now sometimes the servo and ABS come in OK on strart up - but sometimes they don't; I have found that starting up again, without waiting for the whole process may cure it; I cannot get it fixed this week as the dealers are on holiday but I do have to say 1. that the brakes without servo and ABS feel 'reasonable' and that 2. when the servo/ABS are working I really appreciate the effortless brazing and feel that it is a pity that the servo has not been continued on this year's models - a bit ominous!

 

[Gonzo]

I had this issue about a year ago and after having read some of the more "scaremongering" posts on the board, I was ready to be recovered and have the warranty do its stuff.

However, after a 60 mile ride home on residual braking in the dark (not too bad actually ), I checked the bike out in daylight the next day. The switch cover near the rear brake lever had become dislodged and gave the braking system the message that the rear brake lever was constantly depressed. This meant that during the start-up check, the electronics thought that there was a fault (which is why you should never hold the lever during start-up) and completely disabled the servos.

Embarrassing dealer event averted and fixed in 60 seconds.

 

[aspad]

I thought a top up charge had cured this but it hasn't. Now sometimes the servo and ABS come in OK on strart up - but sometimes they don't; I have found that starting up again, without waiting for the whole process may cure it; I cannot get it fixed this week as the dealers are on holiday but I do have to say 1. that the brakes without servo and ABS feel 'reasonable' and that 2. when the servo/ABS are working I really appreciate the effortless brazing and feel that it is a pity that the servo has not been continued on this year's models - a bit ominous!

Hi Brian,
See my earlier post - this sounds very much like the problem I had. My guess it is almost certainly a switch alignment issue either front or back - check horizontal play in the front brake and see if it makes a difference (hold lever in different positions during during start to see if that makes a difference + check linkages/contacts on the rear

 

[Brian ROSEN]

Thanks Aspad

Talk about longe range conversations - advice from Australia to France via the UK. Anyway many thanks - After all my ideas and advice I checked again very carefully and the front brake leaver was just touching the hand guard after all that !!!! All is well now.

 

[Dan79]

I had this issue about a year ago and after having read some of the more "scaremongering" posts on the board, I was ready to be recovered and have the warranty do its stuff.

However, after a 60 mile ride home on residual braking in the dark (not too bad actually ), I checked the bike out in daylight the next day. The switch cover near the rear brake lever had become dislodged and gave the braking system the message that the rear brake lever was constantly depressed. This meant that during the start-up check, the electronics thought that there was a fault (which is why you should never hold the lever during start-up) and completely disabled the servos.

Embarrassing dealer event averted and fixed in 60 seconds.

Update - my bike is now fixed - the switch cover on the rear brake lever (referred to above) was completely missing.... Unfortunately for me too late to avoid an embarrassing dealer event However, all fixed and back on the road again so now i can go out to play tomorrow

 

[bobsayshello]

Update - my bike is now fixed - the switch cover on the rear brake lever (referred to above) was completely missing.... Unfortunately for me too late to avoid an embarrassing dealer event However, all fixed and back on the road again so now i can go out to play tomorrow

All I can say is 'this forum is worth its weight in gold!'

my 'brake failure' light refused to go out after I had an embarrassing 'off' off-road (thats just a polite way of saying it fell over on uneven ground) anywayyyyyyyyyyyyyyy...............

............... got home and did a forum search for 'brake failure + flashing' and bingo..seen this thread! Im not sure if it was the handguard slipping or the rear brake cover but i twiddled both, took the bike out and no more flashing brake failure light