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One More ABS question


dave_a

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1999 R1100R 45k miles

I have replaced, flushed and bled F&R brake fluid completely. I have come to realize (by reading posts on this fine forum) that I have not flushed out the ABS system by doing this. My Clymer manual is unclear how to accomplish this.

Could someone please outline the step by step procedure to completely change the fluid on the ABS unit?

I believe this bike has the earliest version of BMW's ABS system. I am not sure about that. The entire braking system is acting normal, with no fault lights or other issues, other than a slight bit of front "pump up" at the lever. A little bit of air somewhere.

I bleed with a Mity-vac and/or the conventional tube in a jar methods.

Thanks/Dave

 

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I say you have bled and flushed everything, if the brakes feel the same as before flushing, you are good to ride.

 

Dan.

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Dave, your ABS-II system has one single brake fluid circuit for each, front and rear. When you put new fluid in the master cylinder reservoir and bleed fluid until new fluid comes out at the caliper, then new fluid has flushed through the ABS system. Is it possible that there is a little nook tucked inside the ABS that somehow didn't mix with the fresh fluid? Sure, it's possible, but pretty unlikely and not going to affect it.

 

But, if you are determined to bleed your ABS pump, there are a couple of bleed screws on the top of the ABS-II unit. One for the front circuit, the other for the rear. You could put a clear hose on the bleed screw, put a little pressure on the brake lever and then "crack open" the bleed screw on the ABS for just a split second. What you will probable get is an inch or so of fresh clean brake fluid. But, maybe you'll get a few drops of dark older fluid and feel good.

 

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1999 R1100R 45k miles

I have replaced, flushed and bled F&R brake fluid completely. I have come to realize (by reading posts on this fine forum) that I have not flushed out the ABS system by doing this. My Clymer manual is unclear how to accomplish this.

Could someone please outline the step by step procedure to completely change the fluid on the ABS unit?

I believe this bike has the earliest version of BMW's ABS system. I am not sure about that. The entire braking system is acting normal, with no fault lights or other issues, other than a slight bit of front "pump up" at the lever. A little bit of air somewhere.

I bleed with a Mity-vac and/or the conventional tube in a jar methods.

Thanks/Dave

 

Afternoon Dave

 

As mentioned you can bleed at the 2 ABS controller bleeders & that will get most of what you missed but not all.

 

If you want to get as much as possible then, first ride the bike briskly on a gravel or dirt road, then stop hard enough to get into ABS mode on both front & rear wheels (this will cycle the ABS pistons & cycle internal ABS valving to move most old fluid & air out into the main fluid chamber)

 

Then, bleed at the ABS controller top bleed fittings, then fully bleed the front & rear at the caliper bleeders, then go back & re-bleed at the ABS controller bleeders again. (not much more the you can do)

 

 

kGL5N9f.jpg

 

 

 

 

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