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Discussion Starter · #1 · (Edited)
Hi all

I have an 04 (post-facelift) LT with the Integral ABS (BMW front calipers).

A couple of days ago, whilst making a u-turn, my front wheel skidded on some mud at the edge of the road and I dropped the bike onto its right hand side.
I was effectively stationary and no (more) damage was done to the bike. The engine was running in gear for maybe 2 or 3 seconds before I got to the kill switch. However, when I picked the bike up and restarted, the low-fluid warning was on ('Brake failure' and '!' alternating once per second).

When I got home I topped up the reservoir under the rear seat (it was low, but still >minimum) and the front reservoir (only slightly less than full) but the warning is remaining.

I see this referred to in passing on another active thread here (http://www.bmwlt.com/forums/showthread.php?t=87985) with the suggestion that the computer needs a reset, but with a later response that this should happen automatically for the Integral ABS.

[edit - or is it the earlier ABS that resets? I'm not sure now..]

Any suggestions?

Thanks in advance.

Nick
 

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2005 K1200LT
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Did you top up both halves of the under seat reservoir? They are separate and very sensitive to fluid level. Those two are the only ones that are monitored for fluid level. Disregard the level and top them both off.
 

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could have bent the foot brake lever a tad and its holding open the switch so the abs cant reset, check and see if your brake light is on while key is on ign, listen for abs pump it shouldnt be whining.
 

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Discussion Starter · #4 ·
Hey guys, thanks for the replies.

Did you top up both halves of the under seat reservoir? They are separate and very sensitive to fluid level. Those two are the only ones that are monitored for fluid level. Disregard the level and top them both off.
I believe the multi-chamber reservoir is fitted to pre-04 ABSII systems; I've only got a single reservoir.

could have bent the foot brake lever a tad and its holding open the switch so the abs cant reset, check and see if your brake light is on while key is on ign, listen for abs pump it shouldnt be whining.
With the ignition on, the pump starts when I press the brake pedal and stops when I release it, so I don't think that's it either.

Can anyone else help?
I suppose I could try flushing and bleeding the system (I see this suggested in other posts here) but it seems like a bit of an effort - I have to make a special threaded funnel and so on.
I guess I could also get a garage to read and try resetting the fault codes.

Could air have got into the ABS unit somehow, and would that need to be manually flushed, or would it pump it out automatically?

Perhaps I should add that both brakes are working perfectly (though I can't vouch for ABS itself - I don't plan to test that!)

Nick
 

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not likely to have got air, I dropped mine heaps of times, so your saying your reservoir doesnt look the same as pic 1 above cause I think it should
 

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Discussion Starter · #6 ·
Hi Linton

not likely to have got air, I dropped mine heaps of times, so your saying your reservoir doesnt look the same as pic 1 above cause I think it should
We're talking about the reservoir beneath the rear seat, which is visible through the 'window' behind the right pannier, aren't we? Mine is a single cylindrical thing. The Clymer says the dual reservoir is on the older bikes only.

I've dropped mine on more than one occasion in the past too, and have never had this problem before. But the engine was running for a couple of seconds this time - normally I manage to kill it as it goes down. Perhaps the servo pump was running too, if it landed on the brake lever.

Nick
 

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yes that's the one we are talking about, a picture is worth a thousand words they say, not what I expected to see, that's as far as I can go. :( some one else will shed some light I am sure.
good luck
Linton
 

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Hi Linton

We're talking about the reservoir beneath the rear seat, which is visible through the 'window' behind the right pannier, aren't we? Mine is a single cylindrical thing. The Clymer says the dual reservoir is on the older bikes only.

I've dropped mine on more than one occasion in the past too, and have never had this problem before. But the engine was running for a couple of seconds this time - normally I manage to kill it as it goes down. Perhaps the servo pump was running too, if it landed on the brake lever.

Nick
Because you have a 2004 model from Europe, there is confusion here on many posts. In USA, they got the new facelift models only in 2005 - but in Europe it was in 2004.

The later facelift models have the 2 sections reservoirs embedded on top of the ABS modulator. These are the ONLY fluid reservoir monitored by the system on later models - this where you need to fill the brake fluid to avoid certain faults. Keep in mind that some faults sequence (warning on dash) are not related to low fluid level.

See attached picture where the yellow arrows are pointing - these 2 caps are not easy to reach because of the sub-frame tube on top. These caps will unscrew in a normal fashion, but are difficult to access with regular tools.

The single reservoir you have shown in your picture (for rear master-cylinder) is also important but there is no level monitoring switch into this one.
 

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My 2000 did the same thing and I had to do a reset with the 911 tool. It was because one wheel was still turning (the rear) while the front was not or vice a versa.

Alan Hinman
2002 K1200 LT
 

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My 2000 did the same thing and I had to do a reset with the 911 tool. It was because one wheel was still turning (the rear) while the front was not or vice a versa.

Alan Hinman
2002 K1200 LT
YES, a reset can be required for earlier models with ABSII (mainly 1999-2001 in USA). But, the original problem request is for a 2004, so his bike is equipped with IABS (Integral-ABS with servos).

The IABS system is self-check at every power-up and does not need a reset to clear an old pending faults. As long as the fault is gone on next ignition-ON, you are OK. You still have 1 flashing light under normal condition (until you start moving) but this is normal behavior.
 

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Discussion Starter · #11 ·
Thanks guys for all the useful information there.

Guess I'll strip some of the panels off and try filling the ABS unit directly. Shame they aren't fixed on with velcro, the amount of time I seem to spend removing them! :)

If it works I'll post the results back here in case anyone else stumbles across the thread in the distant future.

Nick
 

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Thanks guys for all the useful information there.

Guess I'll strip some of the panels off and try filling the ABS unit directly. Shame they aren't fixed on with velcro, the amount of time I seem to spend removing them! :)

If it works I'll post the results back here in case anyone else stumbles across the thread in the distant future.

Nick
Hold the vent hose of each cap with one hand while you use a HEX key (allen) to turn each black plastic cap. Watch for a small rubber seal (or O-ring) under each cap that may stick to the modulator unit (instead of the cap).

Fluid level can be made full, but normally it is proportionate to wear of the pads - max level under cap when brake pads are new. Otherwise, next time you compress caliper piston to remove wheel, there will be a bit of overflow in vent hose. Min level should be reached ONLY when brake pads are very thin.
 

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Hey guys, thanks for the replies.
I believe the multi-chamber reservoir is fitted to pre-04 ABSII systems; I've only got a single reservoir.
My bad I read your post as to an 04 PRE-face lift and thought that was odd. Now I realize it was post facelift. In that case the reservoirs are ON the ABS unit.

Either one could be low.

This shows the top view (with the caps removed) and the other one shows my flushing set up to give you an idea where to look. 8 mm allen to remove the caps.
 

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Discussion Starter · #14 ·
Hi all.

Just wanted to report back that this problem is fixed.

I used a small syringe to put 15mls of fluid in the left reservoir and about 32ml in the right. The warning didn't extinguish until the level was right up to the threaded section - I was a little concerned at first that too much fluid could cause additional problems, but then I realised that those pipes coming out of the top of the caps are actually just overflows which vent beneath the engine. I guess that explains where the fluid went whilst the bike was on its side too.

It's a little surprising that the hygroscopic brake fluid is permanently open to the air like that although I guess some air has to come in to allow for fluid drop as the pads wear.

Anyway, thanks for all the help.

Nick
 

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I cut the breather hose just where it goes through the nylon guide ring under the seat and installed a miniature in-line dessicant filter (from the instrument section at my work (shhhhh). There's no air flow through the breather line as you are aware, so the dessicant may act as a barrier against moisture. Only time will tell, hopefully my brake module will be happy for years to come.;)
 

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Hi all.

Just wanted to report back that this problem is fixed.

I used a small syringe to put 15mls of fluid in the left reservoir and about 32ml in the right. The warning didn't extinguish until the level was right up to the threaded section - I was a little concerned at first that too much fluid could cause additional problems, but then I realised that those pipes coming out of the top of the caps are actually just overflows which vent beneath the engine. I guess that explains where the fluid went whilst the bike was on its side too.

It's a little surprising that the hygroscopic brake fluid is permanently open to the air like that although I guess some air has to come in to allow for fluid drop as the pads wear.

Anyway, thanks for all the help.

Nick
That is why most cars have a rubber bladder under the master cylinder cap. Not sure why more bike makers don't do that also to keep the air and fluid separated.
 
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