from the BMW of N.A. Moto Training manual ABS system overview 12 pgs

http://forum.kforum-tech.com/members-upload/uploads/ABS_SYSTEM_OVERVIEW.pdf

volador wrote:from the BMW of N.A. Moto Training manual ABS system overview 12 pgs

http://forum.kforum-tech.com/members-upload/uploads/ABS_SYSTEM_OVERVIEW.pdf

Hi I am new to this forum and am looking for some advice. I hav3e a 1990 k100 Rs 16 valve with ABS.

Recently I have noticed that when riding and I apply the rear brake everything works ok for abour2/10th of a mile then The rear brake seems to stick when pressed down about an inch then it will not move at all when pressed, you can stand on the brake lever and it will not move. After this happens the ABS warning lights come on and the brakes return to normal use. All this happens in 3/10s of a mile.

No-fault codes show on my monitor and each time I reset ABS system the same thing happens. I have replaced the ABS brain with another and the same thing happens. I am about to replace the rear modulator as I can't think of anything else.

I would be grateful for any help.

Thanks 

Ian

Do you still have the original brake lines on your bike?  What you describe sounds a lot like the lining collapsing in the brake line.  This can cause trouble in two ways, first is that it only allows the brake fluid to flow easily in only one direction, holding the pressure in the caliper.  The second way is by shedding bits of rubber that plug the banjo fittings, usually the plugging is at the fitting on the caliper.

Does someone digs deeper into ABS system in order to help me make rear wheel ABS assistance switchable ON/OFF while keeping front wheel assistance ON?
Thinking of playing with error signal wire from rear ABS module to ABS ECU. But not knowing what type of signal is it.

Off the top of my head I would guess that the easiest way would be to switch the modulator off while switching on a simulated load to fool the ABS brain into thinking the modulator is still there. The trouble is, I don't know what the brain checks to confirm the modulator operation.

If you don't get the brain fooled, it will turn off the ABS and flash the warning light at you until you smash the instrument pod.

Thinking of working in this area. Thing is that I have no clue what type of monitoring is on that wire. I am just hoping that is analogical to work easier on it.
Still I will appreciate community help.