Intermittent Brake failier, red light

[VAL. H.]

I have recently been getting the flashing brake failure red light and red warning triangle. It happens after only a few minutes or riding. If I stop, turn off the ignition and restart it returns again with in a few hundred yards.

After usually three or four times the reset works and everything is fine for the rest of the ride. When the light first comes on the brakes become completely independent and hyper sensitive (I'm guessing no ABS). The last reset is often when the braking has gone right down to residual braking mode.

The bike is a 2005 Servo ABS. A full BMW Dealer (Bath road motorcycles, previously Bristol Motorrad) service (the big one) was carrid out August last year 2013. at 59000ish miles, less than three thousand miles ago.

Can anyone tell me what the likely cause could be. Are we talking an electrical issue, or mechanical. Is a brake fluid flush possibly the answer. Or am I looking at a hardware replacement job.


Val.

 

[Deleted account 190920001]

Without getting some diagnostic readings from a 911 or dealer it's pretty hard to diagnose.
If your speedo is working OK though it might be the stuck/worn brushes in the pump. Seems fairly common and will be accompanied by no whirring when it has failed. Hitting the pump with a rubber mallet will often help for a while This is just a total guess though.
If your speedo isn't working right then look at the speed sensor.
It could also be a front sensor but I wouldn't really expect that to be intermittent.
Diagnostic information would point you to the right area pretty quickly.

 

[socket086]

it might be it just needs a top up at the pump reservoir under the tank if your lucky

 

[Bendy toy]

Before topping up fluid check the brake pads. Don't want overflowing fluid when new pads are fitted.

 

[beatmeier]

Other than the things mentioned there can be water or a bulb with corrosion in the tail light Had this issue ages ago.When winter starts and things don't dry out anymore the chances get bigger

 

[VAL. H.]

Without getting some diagnostic readings from a 911 or dealer it's pretty hard to diagnose.
If your speedo is working OK though it might be the stuck/worn brushes in the pump. Seems fairly common and will be accompanied by no whirring when it has failed. Hitting the pump with a rubber mallet will often help for a while This is just a total guess though.
If your speedo isn't working right then look at the speed sensor.
It could also be a front sensor but I wouldn't really expect that to be intermittent.
Diagnostic information would point you to the right area pretty quickly.

Servo motor still working ok, or at least. How would I know if the speedo's not working? When it appears to function as it should. Is there some back ground stuff going on in there, as in the ECU?

Other than the things mentioned there can be water or a bulb with corrosion in the tail light Had this issue ages ago.When winter starts and things don't dry out anymore the chances get bigger

Interesting, How does water/corrosion in the rear light affect the braking system?


Val.

 

[Deleted account 190920001]

The speedo does what it is told by the ecu which gets its information from the rear speed sensor. If your speedo it working then the sensor must be OK.

 

[fizzer]

yes corrosion in the tail lamp will give you those symptoms,its a common fault.

 

[alex_rsa]

Bad news is the ABS system is probably broken. Exactly the same happened to mine and in the end you reach a stage where no amount of resetting will fix the issue.

There is nothing to hit, the stuck motor/bushes issue is the later GEN 2 ABS.

If you get the bike onto a GS911 it will show you something like "low pressure in the front circuit" or something similar. If you then try a brake test with the GS911 you will not generate enough pressure. Cycling the iginition may get it to work again but I found this to be temporary.

If you want the ABS to work your choices are 1- BMW or 2 - Motoscot. When I contacted Motoscot the were charging around £500.00 and will need the bike for a few days. BMW will relieve you of something like £1700.00.

Now you are over that shock, what you can do is to remove the ABS. Motorworks sell the parts, there is an OE rear pipe to go from the rear brake cylinder straight to the existing rear brake plumbing. They are also make a front brake pipe to bypass the ABS pump. I have left all the orignal piping and electrics in place. The dash will now illuminate like a Christmas tree so you will need to open up the instruments and carfeully paint over the flashing LED's.

What you have now is a 2005 non-ABS model. Brakes will feel much the same as before the only difference is YOU will need to operate the rear brake as the inter-connection has now gone.

I would of preferred working ABS but it is cost prohibitve to fix and you are only making your bike into a model that BMW did sell.

Hopefully I am wrong but at least you know.


Alex

 

[Bendy toy]

Just a thought.
Can Electrex refurbish the old ABS motor?

 

[VAL. H.]

Bad news is the ABS system is probably broken. Exactly the same happened to mine and in the end you reach a stage where no amount of resetting will fix the issue.

There is nothing to hit, the stuck motor/bushes issue is the later GEN 2 ABS.

If you get the bike onto a GS911 it will show you something like "low pressure in the front circuit" or something similar. If you then try a brake test with the GS911 you will not generate enough pressure. Cycling the iginition may get it to work again but I found this to be temporary.

If you want the ABS to work your choices are 1- BMW or 2 - Motoscot. When I contacted Motoscot the were charging around £500.00 and will need the bike for a few days. BMW will relieve you of something like £1700.00.

Now you are over that shock, what you can do is to remove the ABS. Motorworks sell the parts, there is an OE rear pipe to go from the rear brake cylinder straight to the existing rear brake plumbing. They are also make a front brake pipe to bypass the ABS pump. I have left all the orignal piping and electrics in place. The dash will now illuminate like a Christmas tree so you will need to open up the instruments and carfeully paint over the flashing LED's.

What you have now is a 2005 non-ABS model. Brakes will feel much the same as before the only difference is YOU will need to operate the rear brake as the inter-connection has now gone.

I would of preferred working ABS but it is cost prohibitve to fix and you are only making your bike into a model that BMW did sell.

Hopefully I am wrong but at least you know.


Alex

Bugger.






Thanks for the info, informative.





Val.