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i-ABS fun 2002 R1150RT


Patrick Hendren

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Patrick Hendren

Folks,

 

I have a 2002 R1150RT with servo i-ABS brakes. It was doing the fast brake failure flashing and had the reduced braking power symptoms. An investigation revealed a seized rear caliper and a brake-line leak near the front caliper.

 

I have since replaced the brake lines with steel braided ones and replaced the rear caliper and pads.

 

I have restarted the brake bleed/flush procedure. I have done the front and rear control circuits and have moved to doing the rear brake wheel cylinder circuit. However, when I turn on the key to engage the servo for this part of the procedure, I still have the fast flashing and the servo does not engage.

 

Do I have to clear an error or something before proceeding or does this mean that even with correcting the brake line leak and bad caliper that I may also be dealing with a bad servo unit?

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Fast flashing on the Brake Failure Light with the General Warning Light out means that the self-diagnostics did not complete. One cause of this is a stuck brake light switch. Make sure your brake light turns on and off.

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Patrick Hendren
Fast flashing on the Brake Failure Light with the General Warning Light out means that the self-diagnostics did not complete. One cause of this is a stuck brake light switch. Make sure your brake light turns on and off.

 

I should have added that I checked and confirmed the light comes on when the rear brake light is applied.

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Folks,

 

I have a 2002 R1150RT with servo i-ABS brakes. It was doing the fast brake failure flashing and had the reduced braking power symptoms. An investigation revealed a seized rear caliper and a brake-line leak near the front caliper.

 

I have since replaced the brake lines with steel braided ones and replaced the rear caliper and pads.

 

I have restarted the brake bleed/flush procedure. I have done the front and rear control circuits and have moved to doing the rear brake wheel cylinder circuit. However, when I turn on the key to engage the servo for this part of the procedure, I still have the fast flashing and the servo does not engage.

 

Do I have to clear an error or something before proceeding or does this mean that even with correcting the brake line leak and bad caliper that I may also be dealing with a bad servo unit?

 

Morning Patrick

 

Is your general warning light also on or is it off??? (this makes a difference)-- Let us know if the general warning light is also on.

 

If the general warning light is (off) & the ABS light is flashing fast (about 4 times per second) then that is just telling you that you don't have power assist on either brake circuit.

 

If the general warning light is (off) & the ABS light is flashing slow (about 1 time per second) then that is just telling you that you that the pull away test the hasn't completed yet. (you should still have power assist available).

 

The seized rear caliper should not effect the warning lights or the servo power function (it will reduce braking but not put the warning light on).

 

The leaking brake line could effect the ABS warning lights IF the leak allowed the servo unit to run out of internal brake fluid in that end braking circuit.

 

Are the internal reservoirs inside the ABS controller filled now???? If they are then you still have I-ABS brake controller issues, if the internal reservoirs inside the ABS controller are NOT filled now then fill them & see if your problem goes away.

 

With the general warning light (off) & the ABS light flashing fast (about 4 times per second) that doesn't tell us much other than that you have a brake servo failure & that you have no power assist.

 

To really understand what your problem is you will need to get a GS-911 (or Dealer computer) hooked to your bike & get the ABS failure code (or codes). There is no manual re-set on the BMW I-ABS braking system.

 

 

 

 

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Patrick Hendren

Thank you for your response Dirtrider,

 

General warning light, the one below the ABS flashing light stays on. When I turn the key on both lights come on, top ABS light flashing 4 times a second and the bottom light on steady, you can hear the servo make a noise, there is a slight pause in the flashing but then it goes back to 4 times per second flashing and bottom light on steady.

 

The internal reservoirs are full because I have been working through the bleed/flush procedure. When I first discovered the front brake line leak I also found that the front circuit reservoir was empty. That was before replacing all of the brake lines.

 

I'm going to try going through the procedure twice, in hopes that maybe there is air still present in the lines somewhere since I did replace all the lines. A fools hope, but...

 

 

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Thank you for your response Dirtrider,

 

General warning light, the one below the ABS flashing light stays on. When I turn the key on both lights come on, top ABS light flashing 4 times a second and the bottom light on steady, you can hear the servo make a noise, there is a slight pause in the flashing but then it goes back to 4 times per second flashing and bottom light on steady.

 

The internal reservoirs are full because I have been working through the bleed/flush procedure. When I first discovered the front brake line leak I also found that the front circuit reservoir was empty. That was before replacing all of the brake lines.

 

I'm going to try going through the procedure twice, in hopes that maybe there is air still present in the lines somewhere since I did replace all the lines. A fools hope, but...

 

 

Afternoon Patrick

 

General warning light ON with ABS light flashing at 4 times a second means-- at least one brake circuit in residual braking function mode (no servo assist).

 

Can you get the servo pump (servo assist) to come from either end, hand lever or brake pedal? This might help us pin it down a bit.

 

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Using the hand lever the servo comes on. Using the rear brake pedal, it does not come on. This is my main concern.

 

Afternoon Patrick

 

Your line leak was on the front circuit & your present problem is on the rear brake circuit so as long as the internal controller reservoirs are full & the brake light is coming on when moving the rear brake pedal then your brake problem is most likely inside the brake controller. (usually the pressure sensor).

 

But, without a brake failure code(s) it is mostly a guessing game with no good way to confirm the guess.

 

Do try re-bleeding the rear control circuit (make sure that you remove the little rubber bladder inside the rear master cylinder reservoir before adding brake fluid). Then re-bleed the rear wheel circuit best you can manually (you will have to push on the rear pedal with force) then see what you have. I have my doubts this will help but worth a try.

 

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Patrick Hendren

Thank you dirtrider. My rear caliper was also seized.. so I was hoping that was a partial cause. Seems that the three things are not related and my abs controller is probably bad. I just finished bleeding the control circuits, and will now try bleeding the front, then the rear wheel circuits... just in case.

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Thank you dirtrider. My rear caliper was also seized.. so I was hoping that was a partial cause. Seems that the three things are not related and my abs controller is probably bad. I just finished bleeding the control circuits, and will now try bleeding the front, then the rear wheel circuits... just in case.

 

Evening Patrick

 

Sure it won't hurt to re-bleed but keep in mind that at initial key-on as long as the ABS controller reservoirs are full & the brake switches are closed you shouldn't have a fast flashing ABS light or the general warning light on UNTIL you try to use the brakes even if the control or wheel circuits are full of air.

 

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