• Welcome, Guest! We hope you enjoy the excellent technical knowledge, event information and discussions that the BMW MOA forum provides. Some forum content will be hidden from you if you remain logged out. If you want to view all content, please click the 'Log in' button above and enter your BMW MOA username and password.

    If you are not an MOA member, why not take the time to join the club, so you can enjoy posting on the forum, the BMW Owners News magazine, and all of the discounts and benefits the BMW MOA offers?

  • Beginning April 1st, and running through April 30th, there is a new 2024 BMW MOA Election discussion area within The Club section of the forum. Within this forum area is also a sticky post that provides the ground rules for participating in the Election forum area. Also, the candidates statements are provided. Please read before joining the conversation, because the rules are very specific to maintain civility.

    The Election forum is here: Election Forum

2004 R1150RT: iABS issues, Bubbles in the Funnel tool...

adriancw

New member
Greetings all. First up, apologies for the long intro and explanation, but I wanted some advice on the iABS (Integrated ABS) on my 2004 R1150RT, with 50,000 miles. Advice on the method I've used and what to do next much appreciated...

The problem is that as I attempt to do the ABS Brake Bleed on the front (after completing the rear) - I have bubbles in the Bleed/Flush Funnel !! If you are intrigued, or want to offer advice, please read on and let me know what you think...

I recently went to go for a ride, getting ready for a longer trip and my Brake warning lights came on, both of them!! I wasn't far from home, and pulled over and did the usual start sequence. After a mile, same thing. Not wanting to tempt fate, I repeated this exercise as I slowly made my way home.

After reading these forums, and as it was due a service, and had been sitting for a while, I figured I would follow the instructions (here and elsewhere) on bleeding the brakes and changing the fluids (it has been about 3 - 4 years since last done, and hardly any miles (for a number of reasons) have been put on the bike in the 3 - 4 years.

So after a visit to the Boneyard, I bought the Servo Assist Brake Bleed/Flush Funnel Tool, and some other stuff to do a full service (4 x spark plugs, oil filter, air filter, engine oil, gear oil, alternator drive belt, etc.. I had a few things to help with the actual bleeding (the tubing, non-return valve, and a reservoir).

After removing the fairing and gas tank, even though I had both warning lights - the service on the rear ABS brake bleeding went just as it should. (Note: This was just the ABS Brake bleed, not the the Control Circuits, I was going to do those after completing the Front ABS Brake Bleed...)

So, onto the front ABS Brake bleed. After removing the left & right front brake calipers, removing the pads, inserting suitable wooden blocks against the pistons, I was ready!! I installed the the brake bleed kit (with non-return valve and some fluid in it) onto the still closed left bleed valve.... On the ABS unit I removed the front ABS Brake screw and inserted the funnel in place.

Now the fun begins... After I poured in the Dot 4 Brake fluid and turned on the ignition - I noticed Bubbles!! These carried on for a bit, so I turned the ignition off... When they stopped, and I turned on the ignition and squeezed the front brake lever - more bubbles... This carried on for a while. I eventually figured - what the heck, why not open the brake bleeder and see if bubble come out there and that might help speed up the process.

The result was pretty much the same, Very slow, small amounts of fluid coming out, and occasionally a few small bubbles (I could se the fluid moving slowly, and the bubble moving slightly more rapidly). I was not sure if the bubble were from the ABS unit, or possible leaking in from the threads of the bleed valve. The fluid in the funnel eventually drained lower, to the point where I could remove the funnel

Then, with it sealed again, I removed my bleed tube from the bleed valve, and put some PVC tape (plumbers tape) around the valve threads, put it back in, and repeated the process. same result. Slow steady stream of bubble appearing in the funnel, occasional bubbles in the tube up to the non-return valve after opening the valve. I think there might still be some air getting in through the tape and threads causing those bubbles.

The brake fluid coming out (albeit slowly) is dark, and showing it's age...

Other symptoms to note: The "General" warning light (lower red light) is occasionally off after a few seconds (as it should be), and most of the time has stayed on. The ABS Warning Light (top red light) is flashing rapidly (around 4 times a second...). The Servo's do not start making noise until the front brake lever is squeezed. Then they run continuously, until the ignition is turned off, and I repeat the cycle all over again. Upon starting again, the servos are not running, until I squeeze...

Other than a new/replacement ABS unit, I was thinking of getting a new fully charged battery (current one is showing and holding a full charge but is about 5 years old). I have not checked any relays or fuses, but everything is working (lights, horn, turn signals, starter motor...). The brake lines are all original, and might benefit from being replaced by a set of Spiegler brake lines.

I have just ordered the full set of Speed Bleeder valves for my year and model. Once these are installed, I would expect that I will have removed the possibility of air getting back into the ABS/Brake lines, or showing up in the pipe to the non-return valve.

If you have read this far - any thoughts or suggestions would be most gratefully (and gracefully) received. Cheers, Adrian

PS: I've tried adding Image(s) below show my setup...

Overall.jpg

Left Front Caliper.jpg

Funnel.jpg
 
The Servo's do not start making noise until the front brake lever is squeezed. Then they run continuously, until the ignition is turned off, and I repeat the cycle all over again. Upon starting again, the servos are not running, until I squeeze...

A friend owns a K1200LT which has essentially the same iABS module as your RT. His is doing the same thing, and the diagnosis is a faulty pressure sensor inside the module. Repair parts are practically impossible to find, so I'm helping him with the task of removing his ABS.

But you have not yet flushed the control circuits, which is where the pressure sensor is. Maybe try that and see if it gets the servos working properly.

As for the bubbles: the iABS module on my 2003 R1150RT developed a crack or some other kind of leak in the body of the module itself. The evidence was the rear wheel circuit running out of brake fluid after a couple of weeks, brake fluid sitting in the tray that holds the module, but no signs of leaks anywhere else. Are your ABS module and its tray dry?
 
A friend owns a K1200LT which has essentially the same iABS module as your RT. His is doing the same thing, and the diagnosis is a faulty pressure sensor inside the module. Repair parts are practically impossible to find, so I'm helping him with the task of removing his ABS.

But you have not yet flushed the control circuits, which is where the pressure sensor is. Maybe try that and see if it gets the servos working properly.

As for the bubbles: the iABS module on my 2003 R1150RT developed a crack or some other kind of leak in the body of the module itself. The evidence was the rear wheel circuit running out of brake fluid after a couple of weeks, brake fluid sitting in the tray that holds the module, but no signs of leaks anywhere else. Are your ABS module and its tray dry?


Thanks for the response, and a great idea to continue and try the Control Circuits. I had thought they might be totally separate and independent, which is why I held off trying that.

I am delaying any more work for now as I am about to drive (urgh...) to the national rally in Doswell (or Richmond, VA).

Good luck helping your friend with his K1200LT.

Cheers, Adrian (Charlie)
 
This service link is helpful.
https://www.advrider.com/f/resources/abs-3-service-v2-0.7/

It appears that you have the original rubber brake lines. They are very prone to failure at this age.
Consider upgrading them to Stainless Steel Teflon lines.
Spiegler brand is the go to.
https://spieglerusa.com/brakes/brak...t-rear-brake-line-kit-r-1150-rt-s-bm0172.html

Be sure to specify if you have bar risers so the upper front master line can be correctly sized.


Hi GSAddict,

Thanks for the response. I was thinking the same way as your suggestion, and getting new replacement brakes lines from Spiegler. It will depend on whether the ABS unit eventually works or not...

My alternatives seem to be limited on that, possibly repairing it, replacing it, or removing the whole thing and having a non-servo, non-ABS set of disc brakes (like they all used to be).

Cheers, Adrian (Charlie)
 
Back
Top