Solution for bypassing ABS unit on R1100S

[ride4fun]

Hello,

After having researched a lot the topic of "bypassing" the ABS unit of my 2004 R1100S (following inquiries about trying to figure out what was wrong with it), I decided to bypass the unit. All the procedures I found do some kind of permanent damage to some component. This is problematic for me because, although I know that the ABS is not working (the code indicates some kind of pressure issue), I am not certain that the ABS unit is actually defective. Therefore I want to keep the components in their original state. I am posting this for the benefit of the community.

First the hydraulics. A company in England, Motorworks Ltd, has developed (late 2022) a physical replacement unit, BRA9000, which takes the place of the existing ABS unit (with shipping to the USA, I paid about $240). All you have to do is disconnect the lines, remove the old unit, install the new "frame" and reconnect the lines.

Regarding the electrical aspects. All the articles I found cut the cable that feeds the ABS unit - this is kind of unfortunate, because once damaged, there is no way to go back (at least in a clean way). See the wiring schematic on how to connect components together. Overall it involves the following areas: 1) removing the ABS relay from its socket (this takes care of the warning light), 2) providing power to the license plate / fog light (pins 5 & 6), 3) powering the relay control coil with power when NONE of the break levers are depressed (the relay is "Normally Closed" - NC) (pins 3, 39, 40, 41, 27, R1, R2), and 4) providing power to the break light through the relay switch (pins 3, R3, R4, 4). This works because the relay is "Normally Closed". See pictures for the two configurations. Note that, when none of the break levers are depressed, the relay is energized to keep it open (to keep the break light off). This appears to be unusual, but this must be to provide a failsafe approach. See the wiring prototype to see all the connections.

Let's note that pins 3, 4, 5 & 6 take blades that are 0.110" wide and 0.020" thick (you need to buy them from an electronics store like Digikey - normal automotive blades are too wide/thick). The other ones are 0.015" in diameter (standard electronic terminal pins work fine).

There is only one issue left: keeping all the wires together and the setup shown (initial prototype) needs to be compacted. So I am planning to design a PCB to plug into that connector that will also hold the mini relay.







I hope this helps.

[ride4fun]

I am adding the photo that do not display on the original post (although I see them listed in the post).




Regards.

[R1100S-Slick]

Thanks that is very useful!

[ride4fun]

FYI: Apparently, there are two variations for driving the speedometer on the R1100S, which can be differentiated by the two of brake calipers: Brembo or BMW.

With the Bembo type, the speedometer is driven by a sensor in the shaft; whereas with the BMW type, the speedometer is driven by the ABS unit (as is the case with mine - I found out the hard way!).

This means that the proposed wiring disables the speedometer (when the front brakes have the BMW label on them). In this case the ABS controller needs to be maintained, using the original ABS cable/connector (and the proposed wiring cannot be used).

[sgoodwin]

I removed everything except the ecu for the abs on my '99. It removed about 15 pounds of weight, most of it up high & simply ran lines directly from master cylinder to calipers creating a great feeling & solid stopping brake system & much improved turn in with none of the weird Alice plumbing as above. The speedo sensor is on the final drive not the drive shaft. Search posts on here explaining the steps for the newer assisted braking system as it requires a bit more work because of the speedo & brake light connection with the abs.

[Ridgetopboy]

Ride4fun's method seems like $240 down the proverbial drain. Keep the ECU, get rid of 15 pounds of ugly, and replace those dangerous rubber brake lines with SS braided ones (which you need to do regardless!). Your speedo, etc. will continue to work as expected and your brakes will feel better. That iABS unit was some engineer's wet dream but the execution sucked. I live in the mountains and have a 1200' steep winding driveway that isn't paved very well and gets a lot of "forest smegma" on it. the iABS unit would pulse so slowly that when dragging the rear brake the wheels would lock, skid, then unlock, and roll again. It was obnoxious and scary. Modern ABS units are a huge safety advantage but that iABS...not!

Oh, the ABS light will continue to warn you so I just stuffed a piece of black rubber material in the little indentation the light sits in on the instrument cluster, no more annoying warning light. Jettisoning the mechanical ABS box and replacing the lead acid battery with a Li Ion battery shaved 23 lbs off the bike.

[njsax]

Originally Posted by Ridgetopboy

... I live in the mountains and have a 1200' steep winding driveway that isn't paved very well ...

Your personal disappointment due to your driveway doesn't mean that everyone else has a problem. Your situation is a bit unique. Catching and releasing over intermittent slippery stuff tells me that the ABS was working just fine. In other words, if it wasn't catching and releasing for you, then it wouldn't have been working properly.

If you kept your driveway clean I daresay that you wouldn't have had any problem. Likewise, if there had been an ABS defeat switch (like on the R1200S), you could have switched it off for the trip down your driveway and then flipped it back on once you were on the road and underway. Installing such a switch might have been a better, and more elegant, solution than gutting the ABS.

Maybe the new ABS units would work better for you, but truthfully, I don't see how. Sounds like you're just not an ABS guy. Mine have been working fine for me for years. I don't see any reason to bash BMW.

[sgoodwin]

I totally disagree with you, their ABS is dangerous because of exactly what is said by Ridgetopboy & my own personal experiences with it. It lets go exactly when you need braking not some stupid nanny system interfering & freewheeling at the most inopportune moment. Twice it tried to kill me once over railroad tracks with debris on the road & once in the mountains sending me flying off road. I removed it as soon as I got back to civilization & never regretted it ever. If all you ever ride is perfectly groomed smooth roads maybe it won't kill you but otherwise it's a completely stupid idea. I say learn how to ride instead of relying on nanny devices.

[signit98]

I removed my ABS many moons ago (report in here somewhere) and did the direct connect with braided lines... never looked back.

This "invention" just adds some more complication... unwanted and not needed. It's a solution for a self-created problem.

The warning light was solved by pulling the fuse, if I remember correctly... no issues with anything else.

[Ridgetopboy]

Originally Posted by njsax

Your personal disappointment due to your driveway doesn't mean that everyone else has a problem. Your situation is a bit unique. Catching and releasing over intermittent slippery stuff tells me that the ABS was working just fine. In other words, if it wasn't catching and releasing for you, then it wouldn't have been working properly.

If you kept your driveway clean I daresay that you wouldn't have had any problem. Likewise, if there had been an ABS defeat switch (like on the R1200S), you could have switched it off for the trip down your driveway and then flipped it back on once you were on the road and underway. Installing such a switch might have been a better, and more elegant, solution than gutting the ABS.

Maybe the new ABS units would work better for you, but truthfully, I don't see how. Sounds like you're just not an ABS guy. Mine have been working fine for me for years. I don't see any reason to bash BMW.

I never said my “ personal problem” ad anything but. The point is that the iABS is mot a modern system that uses a microprocessor to control the brakes several thousand time a second, it is a mechanical nightmare that neither made my life better or safer.