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Took a chance on a 02' K1200LT

henri2015 said:
Key switched to on, iABS self diagnosis sequence performed as described in the manual. Pushed start and ran smooth however after starting I have alternating brake warning lights at 1hz. Rolled down our road, front and rear brakes seem to work perfectly. I can hear a hum from what I think is the assist pump when the brakes are applied.
Any thoughts on this condition are appreciated.
This engine is smooth!
Click to expand...

Good signs. The alternating 1hz lights usually indicate either failure to complete self-test/reset (low battery commonly causes this) or low fluid level in one or both of the two brake fluid reservoirs. Check/top up the fluid in the paired reservoirs (RH side of bike by rear tire, underneath the plastic) then try another test ride. If you still have blinky lights then ride the bike till warm and charged up and pull over and restart the bike, then continue the test ride. Also, the whizzy brake bikes seem to be happier if you wait to hit the starter button until the self-check is completed. Stealing voltage away during that test can make the brake controller think the battery is insufficient.

Good luck,
DG
 
GTRider said:
Also, the whizzy brake bikes seem to be happier if you wait to hit the starter button until the self-check is completed.

Good luck,
DG
Click to expand...

My bike was not fussy about the self check, but on my wife's bike if the self check was not complete before starting, the servo brakes did not kick in for a few hundred feet.
 
Well as DG suggested checking the paired brake fluid reservoir, the rear one is nearly empty and the front is between max and min. Does the rear reservoir feed the rear caliper etc?
 
I usually think of them as inner and outer rather than front and rear. The innermost reservoir is for the front brakes, the outermost for the rear. Be aware that front and rear brake systems each have two “circuits”— a wheel circuit and a control circuit, and each is bled separately. There are instructions for the process out there on the web, or if you can’t find them LMK and I can dig up a link. Also, be aware that each of those reservoirs incorporates a sensor to alert for low brake fluid, and that’s most likely what is giving you the blinky lights right now.

Top up those reservoirs and try another ride. If all checks out OK, you might consider taking the bike to a dealer for a flush and bleed. It’s one job on the iABS bikes that I recommend dealer service on, unless you really, really into doing your own maintenance and spending $$ for the special tools required. You really don’t want your brakes being questionable, ever.

But for now, top it up and take a ride then report back.
:)
Best,
DG
 
GTRider said:
I usually think of them as inner and outer rather than front and rear. The innermost reservoir is for the front brakes, the outermost for the rear.
Click to expand...

I could not find a good picture of the inner and outer chambers of the reservoir at back of the bike.
This picture of my bike shows the funnel screwed into the inner most chamber.

IMG_0240.jpg

In post #5 if you fast forward to 13:05 you can see the funnel screwed into the outer chamber.
 
henri I always bled the wheel circuit myself using a beemerboneyard funnel.
Here's the link for the funnel
https://www.beemerboneyard.com/abs3funnel.html

For the control circuit I would remove the bodywork, then ride to the shop and have them do the control circuit.
It was no problem riding the RS the 360 miles round trip to the dealer with the bodywork stripped.
I don't know if there's any problem riding the LT stripped.
At least your are close to a dealer.
 
While you are at it...

Lots of great information on this thread and I also thought I would recommend that if the bike has the original rubber brake lines, that you replace those with braided stainless lines. My 2005 LT was a Museum piece and sat up for years, the rubber lines were in horrible shape and one of the front lines ruptured within a 1000 miles or so. It had 11,000 when I bought it in 2013. Spiegler makes them fit for the bike.

The website bmwlt.com had tons of great information about these bikes as well.

Chris
 
Got the brake fluid topped up. General warning light is now off but brake failure light is still blinking at 1 hz. Rear master circuit was very low. Brakes work great, servo hums when it should all seems to function properly.
Any thoughts? Maybe a battery disconnect reset?
Thank you,
Dean
 
At this point I’d recommend taking the bike to a dealer for a diagnostic hookup. You might also get some answers with a GS911, but that device may not be able to tell you all you need to know. The reservoirs you topped up could have a non-functional level sensor, which would require replacing the reservoir, or you could possibly have a front or rear master cylinder that is experiencing leak-down and would fail the bleed-down test that occurs at the end of a brake service using the BMW ModiTec unit. And as pointed out earlier, it could be something as simple as a failing brake line holding residual pressure or a mis-adjusted rear MC plunger holding pressure on the system during the self-check.

Rather than flail at the issue, I’d recommend a visit to the dealer and have them hook on the ModiTec and do a flush and bleed. IMHO it would be money well spent at this point, where you’ve already checked the low-hanging fruit.

Best,
DG
 
Since the flush seems to be an important maintenance item I am going to try it. Ordered the funnel from BMW Boneyard. Thats probably the end of my probing.
 
Update, tried the ABS flush. The servo bleeder won't pass any fluid, think its toast or a kidney stone. Anyone document whats reqiured for a ABS bypass?
Dean
 
henri2015 said:
Update, tried the ABS flush. The servo bleeder won't pass any fluid, think its toast or a kidney stone. Anyone document whats reqiured for a ABS bypass?
Dean
Click to expand...

I would again encourage you to get the bike to a dealership and connected to the MoDiTech. If the ABS module is indeed bad, that will show on their diagnostics. Or, it may show that what is needed is a proper flush and bleed, with the MDT cycling the system in the correct order and correct time. And without a proper diagnostic readout you still don’t know that your warning lights aren’t being triggered by a failed level sensor in the reservoirs, or a master cylinder that is failing a leak-down test. Yes, it will cost a few $$ but at least you will be working from a known point.

According to your previous posts right now the booster pumps and brakes are working properly and the system is not going into “residual braking” mode. So by removing the ABS system you won’t gain anything other than disabling the blinking lights, which could be done anyway. And by removing the ABS system you lose the boost on your brakes and you WILL notice the effect from that.

For all of us that like to wrench on our own, there comes a time when dealer service and equipment are a good choice.

Good luck,

DG
 
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