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Discussion Starter #1 (Edited)
Bad day today. I was coming home from work and hit heavy traffic on freeway and lost 80% of my breaking. I managed to pump like crazy and got her stopped. When stopped and bitching Betty flashing away I could hear the pump still running in low mode with engine off and key on on position. I Had 4 flash per second of the ABS warring and the General warring on Solid, which points to abs Unit.

I Microsoft-ed it (rebooted) and error went away. I managed to limp home in side roads under 35 downshifting and light breaking all the way home. I checked all fluids levels and every thing is good and topped off. I went for a quick ride again on my residential street got up t about 25 30 and heavy performed heavy breaking and error came back. Same warning and pump still running with kill switch shut down. Had to cycle ignition to get it to stop.

Bike is still in great shape rebuilt clutch last year can go another 80 K, but with out breaks now :surprise:.....

This weekend I will give it a more detailed going over, but probably looking at a rebuild of an iABS unit. Or a big bill at the dealer for repair, which at that point I may pull the trigger and retire the old girl :crying: and settle on a an upgrade. Shhhhhh don't tell my wife :wink:


I could not find anyone who rebuilds the iABS (iii) units. Does anyone know if there is a place that can do it.Module Masters WEB says they are still in dev. for rebuilds. Sent them an email anyway to see if they want to experiment on mine for a reduce fee.

Or does anyone have any other ideas?
Or have 3K they could loan me to repair a 15 year old bike that I will never pay back :grin:

Ride Safe !!
 

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Simple. Bypass the pump. It's not worth $3K for a 15 year old bike. And even if you wanted to. No one rebuilds them yet. Saddleman bypassed his as have others with fine results.
 

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2005 K1200LT
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Need to get a GS-911 unit to run the codes. There a few that can be fixed by cleaning a relief valve but only a few. Nothing wrong with the by pass but you will lose that wonderful ABS but she will still stop well. The ABS electronics provides the speedo signal so you have to keep that part or no speedo or cruise control.
 

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Discussion Starter #4 (Edited)

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Discussion Starter #5
Simple. Bypass the pump. It's not worth $3K for a 15 year old bike. And even if you wanted to. No one rebuilds them yet. Saddleman bypassed his as have others with fine results.
Any good directions on bypassing the pump James ?
See a few post on folks doing it , but no real good instructions (at least for me to follow along).

Thanks
 

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Contact Saddleman. He's always very helpful. But be absolutely sure the ABS is bad first. As John stated. It could be something repairable
 

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This is an interesting discussion. I have a bad ABS Modulator (part # 34 51 7 685 803) on my 2002 K1200LT. I had it confirmed by my mechanic this weekend. I am not interested in shelling out almost $2K for a new one. During my research to figure out how to do this less expensively, I have learned the following:

Tyler at Module Masters is close to having a re-build option for the ABS module soon. Not sure when, but it sounded like he is in the testing phase right now. So it could be a few months away. I also volunteered by unit for the testing ;-)

I have also been doing the search of the salvage yards who have BMW's. I have a couple of possibles out there, but if any of you have had experience with the used parts market, I would love to get info on your experience on who is trustworthy.

One thing I also learned that you all can confirm or not, is that you have to get a ABS unit that came off of the same model type of BMW. In other words, since mine is a LT, it has to come from an LT. Not a GT. I was told that the sensor in the ABS unit is programmed type specific. Not sure if this is because of weight or other handling characteristics. Thoughts?

I am also interested in the other option posted about by-passing the ABS altogether. What is the downside? Other than having to apply more manual pressure, does it create any other conditions that you all can advise on?
 

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This is an interesting discussion. I have a bad ABS Modulator (part # 34 51 7 685 803) on my 2002 K1200LT. I had it confirmed by my mechanic this weekend. I am not interested in shelling out almost $2K for a new one. During my research to figure out how to do this less expensively, I have learned the following:

Tyler at Module Masters is close to having a re-build option for the ABS module soon. Not sure when, but it sounded like he is in the testing phase right now. So it could be a few months away. I also volunteered by unit for the testing ;-)

I have also been doing the search of the salvage yards who have BMW's. I have a couple of possibles out there, but if any of you have had experience with the used parts market, I would love to get info on your experience on who is trustworthy.

One thing I also learned that you all can confirm or not, is that you have to get a ABS unit that came off of the same model type of BMW. In other words, since mine is a LT, it has to come from an LT. Not a GT. I was told that the sensor in the ABS unit is programmed type specific. Not sure if this is because of weight or other handling characteristics. Thoughts?

I am also interested in the other option posted about by-passing the ABS altogether. What is the downside? Other than having to apply more manual pressure, does it create any other conditions that you all can advise on?
I think they have been a few months away for about four years now. I think a bypass is your best bet. If you do it without altering the existing lines, you can always revert back if MM ever comes through.
 

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I am really interested to know what actually 'fails' on these units? Is the failure normally electronic, or is the failure mechanical in nature? If mechanical, what component has been determined to be unreliable? You never read anything about similar ABS problems on cars... Why do the different models of ABS units on BMW motorcycles fail?

Having some machinist background makes me wonder why replacements for the "failed" parts can't be an easy fix...

Color me "REALLY CURIOUS"...

-John
 

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I am really interested to know what actually 'fails' on these units? Is the failure normally electronic, or is the failure mechanical in nature? If mechanical, what component has been determined to be unreliable? You never read anything about similar ABS problems on cars... Why do the different models of ABS units on BMW motorcycles fail?

Having some machinist background makes me wonder why replacements for the "failed" parts can't be an easy fix...

Color me "REALLY CURIOUS"...

-John
Yes they fail on cars as well as my friends BMW 750 Li was just repaired by MM in Idaho. The biggest problem is when BMW decides that they will not stock repair parts and make things throw away like the EHCS actuator on the 05 + LTs. It is a 1300 item and I have been able to source all the parts that normally wear out so it is an easy rebuild. I even found a source for the pump itself but the MFG has an agreement with BMW to not sell to anyone but BMW.

MM has had difficulty finding a source of internal parts. There are two servo motors/pumps, two relief valves and four pressure transducers. I have seen burned out control boards and fried servo pump motors. Even sent one motor to fellow that was trying to fix his burned out motor. I never head back on his success or failure. There is a chap over in S.A. that has a collection of failed units and has some success fixing others with his spare parts. Mostly on GS versions. So yes if you can locate the parts they are an easy fix!
 

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I looked at the paper someone had posted on another thread where they tore down the earlier ABS pump. Their assessment was that he may have avoided getting a new or rebuilt pump by simply making sure the pistons were not somehow impeded in the cylinders.

Has anyone torn into the iABS pumps for the 2002 or later models? Are they fundamentally the same mechanics with the pistons, high pressure springs, ball bearing check valve, etc.? I would be interested in seeing if the pistons on my "failed" unit could be the impeded and causing the problem.
 

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No they are a bit more complicated with transfer pistons, pressure transducers and servo pumps. Here are a few of the inside looks.
 

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Hi all

The ABS unit failed on my 2004 (European) bike, with the GS911 revealing it to be a high pressure in the rear brake line.

I took the unit out (which was hard enough!) and dismantled the thing down as far as I could. It actually didn't look too bad inside, but I gave it a clean up and put it all back together.
Now, unfortunately, I am unable to generate enough pressure on either the front or rear circuit to get 'into the green' on the GS911 bleed test. Although the brakes work fine initially, as soon as I apply them whilst riding I get the fast flash and both circuits trigger a low-pressure warning.
I can only imagine my dismantling has created a leak within the system. Perhaps I needed to fit new gaskets, or at least apply some sort of sealant. There did seem to be a soft-ish seal around both pressure transducer plates, so maybe they are now leaking fluid. There is also no information on torque settings, so you just have to use what feels about right, I guess, bearing in mind the unit is aluminium!

In hindsight, perhaps I should have just tried removing and cleaning the pressure relief valves, which I think are the black-capped cylinders on the top of the unit (penultimate pic in John's last post). But at the time, I thought the unit would be full of corrosion and dirt inside.

I'm now about to give the German rebuilding company a go. ( Type AM1 ). At €800 it's not cheap, and probably not worth it given the age and condition of the bike, but my alternatives are to buy a new LT, but then I'm still stuck with a ageing bike no longer manufactured, or really shell out for a GTL, which I can't afford right now. So I'm going with a rebuild, and then I'll be fastidious about servicing this bike and just hope nothing else major fails for a couple more years!

One other thought - lots of people here talk about removing the ABS unit and reverting to manual braking. For those that do this, have you told your insurers, and if so, what did they say about it? Maybe the law is different in the US, but I think over here if you had an accident and it turned out you had bypassed the ABS without telling them, it would invalidate your insurance, regardless of the cause of the accident.
For those that do want to do this, it seems RH Electronics now sell something to replace the ABS unit, so you don't have to worry about re-routing pipes etc.

Good luck Rich and everyone else with this problem.

Nick
 

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After doing some reading, according to RHelectronics, the ABS relay seems to be the culprit in many abs failures.
Any thoughts on this, anyone?
 

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After doing some reading, according to RHelectronics, the ABS relay seems to be the culprit in many abs failures.
Any thoughts on this, anyone?
Yes it is for the 99-early 2001 with ABS II (not the servo brakes).
 

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Any ideas what the proper replacement is, or is it the same relay, just new?
 

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164 dollars at max BMW, about the same from Europe. ABS motor relay
 

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Search for a 50 to 70 amp 12v relay there are several out there for under $20. Then just adapt it.
 

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Discussion Starter #19
I finished up the bypass today and went for a ride. Works fine but do miss the integrated braking.
But she stops just fine now with no issues.
 

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Hi Rich,
Do you have step by step instruction how bypass ABS module on K1200rs 2002?
Do you have cruise control and all signals after?

Thank you
Alex
 
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