i ABS Help!!

[John832]

2002 R1150r

Last night while riding my ABS/Gen lights started to flash, alternating flash. Upon inspection I found one of the rear brake calaper bolts broke (rear bolt) I limped home after tightening the other. I have removed and replaced the broken bolt, checked the levels in the brake resevours, charged the battery...still flashing lights. The ABS apears to be working correctly.

I have tried this, hold down both brake levers and then turn on switch...then the lights flash even faster?

Any ideas???

[boxermania]

I don't think a broken bolt will send your ABS on the blink, as the ABS basically looks at lack of rotation of the wheels to activate and that was not affected.....even with a broken bolt the pads will clamp onto the disk, except there would be an increased rotational moment carried by the remaining bolt.....wow, where am I going with this....sorry.

Suggest you check the wiring harness under the steering head as the symptoms point to broken wires under the nylon tie wraps. This is a common occurrence, you will have to slice throught the covering sheath to check/examine the wires.

[John832]

The broken bolt allowed the calaper to travel forward..in the direction of the wheel. I could start hunting down a broken wire but it would appear that something happened in conjunction with the calaper.

[sweatmark]

There are several things that could fault the iABS controller:

low fluid levels in front and/or rear brake circuit, as measured by sensors in the ABS servo module;
faulty wheel motion sensor for either wheel;
the typical problem of low voltage due to dead/dying battery;
broken filament in tail/brake bulb;
busted hand or foot brake switch;
internal fault (electrical or mechanical) within the ABS subsystem.

There might be others, but the diagnostics and logic ladder for the iABS system is not published... at least not that I've found.

First, check your battery - this is usually the cause of blinking ABS lights and owner worries.
Then, check that the rear wheel's ABS motion sensor wiring is intact following the rear caliper bolt issue.
Check front & rear wheel braking performance: is it "normal" or impeded/weak?
Check the tail/brake bulb operation.

Finally, check you wallet. If by small chance the iABS unit has crapped out post-warranty, you're looking at $2-3K for replacement. Unless you rip the iABS out and convert bike to tried, trusty & true non-ABS.

<edit> The rear caliper should not - by itself - produce a fault in the iABS controller. The controller doesn't know or care about the caliper's operation or orientation. The only interaction I can imagine between the bolt loss >> caliper movement >> iABS fault would be dislocation of the caliper such that its pistons fully extended with brake application in the absence of rear brake disk (if caliper rotated forward and cleared all contact with disk), causing excess draw-down of the brake fluid in the rear circuit, and thus tripping fault due to low fluid level. And that's kind of a stretch, though possible.

[John832]

Thanks for the reply, "sweatmark"? You were right on with your assestment by saying to check the fluid levels in the servos. I ended up calling Nicks in Green Bay and John the Service Manager/Owner's son sent me straight to the source. Low fluid in the ABS modulator under the gas tank. These guys, Nicks are great and I recomend them to you all. My only problem with them is they are 200 miles from me! $2000 for a replacement...ouch!! That is crazy.

[snowprick]

John832,

Did you say "broken calliper bolt"??????

Was there any sign of lube or anti seize compound on the threads of the broken bolt?

Those bolts should be torqued down D R Y. That is no lube or anti seize WHATSOEVER anywhere on the bolt.

If there is any doubt, throw the existing bolts. Clean the threaded holes in your callipers / forks and install new bolts DRY to the approved torque.