ABS problem

[jwpzx9r]

Went out up to the mountains today. Got up to a Ski center and stopped for 10 mins to take in the views then headed back down. First corner I came to squeezed the brake lever and the front dipped violently lucky I did not drop it look at the inst panel and the ABS light is flashing and the speedo aint working Nursed it home brakes hardly working at all and ABS light flashing all the way home Anybody any ideas? Begining to think I bought a dog here albeit a very tidy one! I will have to return it to the shop tomorrow see what the score is. I had been enjoying it soo much up to that point as well no sign of the clutch slip then this When I switch the ignition on it goes through it's routine and then I get a buzzing sound and the flashing light!

 

[Spike]

when my ignition is on it goes through the check system but the light for the brakes still flashes till i actally move off.
Have you tired riding the bike since this happend, i.e since you got it home???

spike

 

[jwpzx9r]

I stopped and switched the ignition off then on again and let it go throught the system check light stayed on when I moved off but also the speedometer is not working!! I am pee'd off this has taken the shine right off buying the bike first the clutch (although to be honest you have to be caning it to have a slip problem) but now this I am wondering if BMW's are all they are cracked up to be Can't help but feel the non working speedometer and the ABS light warning are linked some how. I was stunned how poor the brakes are without the ABS functioning how's that??

 

[APE]

What year is the bike are they servo assisted ?

 

[Roymondo]

The ABS and speedo both use the rear wheel speed sensor, so if both systems have stopped working it's very likely the problem is with that sensor. It is tucked away on the inside face of the swing arm/final drive.


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[jwpzx9r]

Its a 2005 model described as having integral sport ABS what ever that means! But I can't help but think that the speedo not working has summat to do with this problem. Even on its own why would the speed suddenly stop working?

 

[solidstate100]

The ABS and speedo both use the rear wheel speed sensor, so if both systems have stopped working it's very likely the problem is with that sensor. It is tucked away on the inside face of the swing arm/final drive.


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+1

Probably the inner face of the sensor needs a clean, and would explain why the brake and speedo isn't working.

Good luck

 

[jwpzx9r]

I will have a look tomorrow and give it a clean. I assume you have to remove the brake caliper to do this?

 

[autogs]

have you checked for play in the rear wheel bearing

 

[Pukmeister]

I will have a look tomorrow and give it a clean. I assume you have to remove the brake caliper to do this?

Nope. Bike on centrestand, remove rear wheel.

The rear wheel sensor is fitted on the rear (inside) face of the final drive at the top, it is a small plastic item with an electrical lead attached to it, held in place by a small Torx screw. Chances are, the screw head will be full of shite, preventing a Torx bit from sitting properly in the full depth of the screw head and getting good purchase:

*IMPORTANT*

Be sure to clean out the screw head and choose the tightest fitting Torx bit you can find, IIRC it is a Torx25 but a Torx20 fits and feels tight, then slips and rounds off the inside of the screw head.

Once the retaining screw is removed, pull out the sensor (which will probably have a Christmas tree of metal filings on it), wipe clean, inspect the sealing O-ring, then replace and refit the screw.

Refit rear wheel and test ride, all should be good again.

 

[Schtum]

have you checked for play in the rear wheel bearing

+1 ISTR that this is often an early warning of the need to replace the final drive bearing.

 

[Steptoe]

+1 ISTR that this is often an early warning of the need to replace the final drive bearing.

Yes, very possibly

 

[jwpzx9r]

Well I have tried to check for play in the rear wheel but to be honest I can't find any but I really don't know if I am checking it properly. I find no play but the bike moves a bit when I try to move the wheel so its difficult to tell but if there is play it must be very minimal I remember the wheel bearings went on my GPZ1100ZX and it was unmistakable, this may be a whole lot more subtle. I have been looking at the service documents for a service carried out at 27772 km the bike has now done 28052 so less than 300km. At the service the final drive was drained as was the gearbox and the oils replaced surely they would have spotted trouble at the service no?? Or maybe they did told the guy and he said flog it, but would the main BMW motorcycle concessionaire in Pau resort to such skullduggery? I am going down tomorrow I hope there is a simple and not expensive explanation.

On a point of safety if I have been honkin on into a sharp cornrer and really needed the brakes I would have been toast because they are F'n crap without the ABS system. Its a real worry, the fact that I had to come down from a mountain pass through a fair few hairpins at between 6-8% gradients was not much fun either.

 

[APE]

On a point of safety if I have been honkin on into a sharp cornrer and really needed the brakes I would have been toast because they are F'n crap without the ABS system. Its a real worry, the fact that I had to come down from a mountain pass through a fair few hairpins at between 6-8% gradients was not much fun either.

I've never owned an early 1200 with ABS but I think the problem is the loss of the electronic servo rather than the loss of ABS. You end up with 'residual braking' ie braking without the servo. Get it looked at / sorted and all will be well again.

 

[JFC]

Same happened to mine - check disk and pads, both worn system goes out of limits and ignores sensors gives brake fail

Replaced and all ok

 

[Bone]

Mine did that a few times when the battery was on its last legs. Since replacing the battery it's been fine.

 

[Lord Vader]

have you checked for play in the rear wheel bearing

As he said. Happened to mine too. First the red triangle of death and the speedo going ape then my final drive went.
4 times

 

[jdel2204]

low level brake fluid (can happen when pads are a bit worn) in the ABS module somethimes causes the "brake failure light" ... and light flashing means residual brake function "on". at least have a look.
brake switch failure (front of rear) may lead to the same issue. simple things to check if I was you.

there was also a "recall" from BMW regarding the front brake lever...if the lever touches the handguard on the rest position the brake switch stay "on". if you turn the bike on with the switch open you get the brake failure light.
idem, but I suppose you did not made the mistake : never turn the bike on while applying the brakes.

 

[Pukmeister]

1. With the early servo ABS bikes, as the pads wear, the ABS pump internal fluid level falls. If it gets too low you may experience brake problems. Note: The level in the handlebar and rear brake reservoirs do not drop as they are pilot circuits for triggering the ABS pump. Replacing the part-worn pads can cure this, as can removing the fuel tank and topping up the servo pump internal reservoirs (however this can then mean the reservoir is overfilled
when new pads do eventually get fitted).

2. If either the front brake lever or rear foot pedal switch are faulty on startup, the ABS system self-check on first startup gives ABS warnings and residual braking only. Fixed by adjusting the switch or freeing the lever from the hand guard.

3. If the speedo and ABS are both a problem, it is usually swarf on the magnetic rear wheel speed sensor. A clean usually fixes it.

4. The servo ABS electronics are sensitive to battery voltage, be sure your battery is in good health. The ABS pump uses a lot of amps when running and can easily overload old or tired batteries.

 

[jwpzx9r]

Well thanks for all the advice and there are many things which could potentially cause my problem, but the bike has just been fully serviced and they said they changed all fluids in the braking system as we as FD and gearbox and gave an annual check. It had a new battery fitted so unless the alternator is not working too good that should be covered as well. I am taking it to the shop this morning they should be able to tell me the fault. If the rear bearing is going I can't feel it but I am not certain that I know exactlly what I am looking for.
Thanks and I'll let you know