Brake issue solved (let's hope so)

Fact : among the 300+ entries published on this blog, the one that draws the more attention and gets the more hits is a post where I describe how to get rid of the I-ABS system on a BMW. My way to do it seems to have been reported and linked on a few forums (like the R1150R forum, for instance). The truth is - and you won't be surprised if you are a frequent reader of this place - I have been struggling with brake issues since the day I put the brake system parts together back on the bike.

Since I (think I) have solved this brake issue today, it's important everyone reading the famous "how to remove your integral ABS system on my beloved BMW" blog entry is also aware of the potential problems that could be met after completing the described procedure. I still don't know (and probably never know) which part to blame yet, but the feeling pulling the brake lever was awfully spongy.

I remember the first thing I did when I decided to remove the ABS unit was to start with cleaned and verified parts, so I had the calipers rebuilt by an official BMW dealer (that I won't recommend by the way ... let's name them so you don't waste your time there : Boxer Evasion in Lille, France). After 3 weeks waiting, they called to say the calipers were ready and complain about having been forced to order 3 different join sets to find out which one fit the calipers. Like I'm supposed to know better which join set to order ... Now who's the professional ? Anyway ...

To solve the spongy brake issue, every single part of the brake system has either been rebuilt or swapped since. But still, the problem remained unchanged. Well this was until I swapped the Tokico calipers for Brembos which are for the same bike, but without the ABS system. So, if you ever experience the "spongy lever" syndrome after discarding the ABS unit the way I described it in the most-read-post-ever on this blog, then you might have to swap your Tokicos for Brembos ... 

The reason for this ? Well, don't forget that you've just junked the I-ABS unit which not only controlled what pressure is to be put through the brake lines, but also uses a  noisy electrical pump to add extra pressure in the lines whenever you pull the bake lever (which is why you have a huge battery by the way). The question is : can these Tokico calipers work properly without the assistance of the pump embedded in the I-ABS unit ? Well I don't know, because there are still chances that the initial caliper rebuild had been f****d up by a BMW dealer that doesn't know which join set to order ...

Ok then, what's to remember of my experience throwing the I-ABS unit away : 

- do it, it's really worth as it's really heavy and can't really compare with the brake feeling you can experience with a simpler system

- if you dumped the I-ABS unit and experience a spongy feeling, then try with straight braided lines

- if you still feel it could be better and haven't asked an inept dealer to rebuild your Tokicos, then you should look for a pair of Brembos

Integral ABS closed circuit

There are numerous questions about BMW's Integral ABS brake system around the web. Mainly to know how to get rid of it. Designed more than 10 years ago now, it's a rather advanced system but when it fails it's really expensive to fix. There's only two cheap cures when this happens : remove it or have it removed.

One other question that comes relatively often is why simple parts from previous generations of ABS systems - such as the ABS-1 - or non-ABS versions of the same motorcycle are not compatible with I-ABS. Well, let's say you've spotted a nice master cylinder for your R1100S on ebay, if you blind buy this part there are a bit more than 50% chances you get one that fit on your I-ABS equipped BMW. And this is the reason why : 

Brake switch when lever relased

Brake switch with lever pulled

The brake loom works as a closed circuit. That is, instead of requiring to be closed, the brake light won't light up if the circuit is not opened. So the brake lever closes the circuit when it's completely released and opens it when at full grab.

This topic has been discussed hundreds times on different forums, but pics are worth thousands lines of explanation.

ABS removal : epilogue (hopefully)

Update : This post draws a lot of attention. Everyone reading this post to discover how to dump the I-ABS unit on his beloved BMW should also read this one about potential issues and how to solve them.

After having searched for days for a valuable solution to get rid of the ABS system on the R1100S, I remember being resigned to give up the idea. This bike's equipped with the I-ABS (stands for Integral-ABS, a version coupling front and rear brakes actions) version of the system and although there seems to have proper solutions to remove previous version of ABS on older R1100S, my searches and requests for help on both american and german forums did not give any result I was pleased with.

But that was until I sent an email to a Pelican Parts board member that seem to have done the job a couple of years ago, but did not describe how to do it. With little hopes of being replied to, I gave it a try. The guy (Jan) replied in less than a day and told me how he did it and how long his bike was running this way. Rather reassuring. Long story short, the way to go is to keep the electronic part of the ABS system and discard the hydrolic one.

Before showing what I did, a couple of words on why not just remove the whole ABS system. Well all the brake hoses have been changed to shorter and more direct routed ones, but that's really not enough. If you simply disconnect the I-ABS unit, the speedometer and brake light will immediately stop working. This is because the I-ABS unit is not just a pump that adds or removes a bit of brake pressure in the system. As with other features, it also computes the ABS sensor signal as a speed signal that is then sent back to the dashboard. Last thing to mention, do not try to bypass the I-ABS module plug : this does not work even if the wire diagram lets you think it will.

Now for the pictures. Here's what to do.

- This is what I started with this morning. Drill the 4 one-way screws retaining the electronic part of the module.

- Gently open and to discover what needs to be unpluged.
- Unplug the wires
- This is what you want to keep

- This is what you want to discard (rather keep it in a safe place as it doesn't come cheap even as a second hand part). And guess what, it apperas to be the heaviest part !

- This is what I ended up with. I cut a piece of metal to close and insulate the electronics.

Now this tiny and light box can be plugged back on to the bike. You now have working speedo and brake lights again. The only problem left is the "brake failure" light flashing on your dashboard. Simply remove the corresponding relay and off it goes (the other warning light is still flashing though, and I don't have a quick trick for that but to unplug a wire directly on the dashboard).