2002 R1150RT brake reverse filling

[thondo]

I am looking specifically for information on how to reverse fill the brake systems on my bike. There is so much info on the proper bleeding of this system but I have read of people using a reverse filling procedure which results in little to no air in the line and no chance of accidently emptying reservoirs. I would like to hear from someone who has done this as I am looking to develop a complete how-to for the rest of us. I am not looking for personal opinions of what I should do or your favorite way. Unless someone has info that this method is unsafe, please just help me or not. Thank you.

[dirtrider]

I am looking specifically for information on how to reverse fill the brake systems on my bike. There is so much info on the proper bleeding of this system but I have read of people using a reverse filling procedure which results in little to no air in the line and no chance of accidently emptying reservoirs. I would like to hear from someone who has done this as I am looking to develop a complete how-to for the rest of us. I am not looking for personal opinions of what I should do or your favorite way. Unless someone has info that this method is unsafe, please just help me or not. Thank you.

 

Morning thondo

 

On the BMW I-ABS system the wheel circuits pass through the servo pumps, therefore using the power servo pumps to bleed the wheel side of the system is probably the best way to get ALL the air out of the wheel circuits.

 

Could you back bleed the wheel circuits?--possibly. I'm just not sure what the gain is as you STILL have to remove the fuel tank to bleed the control circuits.

 

Also, in back bleeding the wheel circuits you still need to access the ABS controller to rig up a plug & hose to dump the back-bled fluid. If you try to back flush it though the controller vent hoses that will fill the vent catch container & have fluid spraying out of the vent hose while riding then blow back on the rear wheel & rear vehicle paint (brake fluid is a great paint remover)

 

If you use a large enough funnel (or I use a water bottle with the spout cut down) there should always be plenty of fluid in the container to prevent draining the reservoirs.

 

I know of many many BMW 1150 riders that do their own brake service but not a one uses any sort of back-bleed procedure.

 

 

 

 

[thondo]

Thanks for the help. I have read so many pages on this now that I am suffering from overload. I believe this is one of the posts that got me wondering about "back bleeding". It seems simpler than all the processes I have run into.

 

http://advrider.com/index.php?threads/help-bleeding-brakes-on-r1150rt.909542/

 

But I see some of the issue you are speaking of now. This system seems so needlessly complex it has me seriously spooked. I feel like if I screw anything up I might as well throw the servo pump away.

 

I think what I need is first, to know what system I actually have, there seems to be a lot of confusion on if it is ABS II or III. And from there, I need a simple block diagram of the system so I can understand fluid flow. I am using this bike but also rebuilding it at the same time. It was my step father's and sat for several years. I just got Spiegler lines for it. I have a number of things that need to be fixed as well but the brakes and clutch lines scare me most. I also have to re cover all of the wiring since all of the sheathing has dry rotted off. Now I also seem to have a right hand blinker switch out since it will not work from the blinker switch but all hazard lights are working. It worked intermittently for about 3 days then stopped. After that, I am saving for and buying clutch parts since I am starting to get a bit of a slip at high torque/RPM. It has about 65k on it with no sign of splne failure so that seems to be a plus. Luckily I don't HAVE to ride it too much right now, maybe a couple hundred miles per month.

[dirtrider]

Thanks for the help. I have read so many pages on this now that I am suffering from overload. I believe this is one of the posts that got me wondering about "back bleeding". It seems simpler than all the processes I have run into.

 

http://advrider.com/index.php?threads/help-bleeding-brakes-on-r1150rt.909542/

 

But I see some of the issue you are speaking of now. This system seems so needlessly complex it has me seriously spooked. I feel like if I screw anything up I might as well throw the servo pump away.

 

I think what I need is first, to know what system I actually have, there seems to be a lot of confusion on if it is ABS II or III. And from there, I need a simple block diagram of the system so I can understand fluid flow. I am using this bike but also rebuilding it at the same time. It was my step father's and sat for several years. I just got Spiegler lines for it. I have a number of things that need to be fixed as well but the brakes and clutch lines scare me most. I also have to re cover all of the wiring since all of the sheathing has dry rotted off. Now I also seem to have a right hand blinker switch out since it will not work from the blinker switch but all hazard lights are working. It worked intermittently for about 3 days then stopped. After that, I am saving for and buying clutch parts since I am starting to get a bit of a slip at high torque/RPM. It has about 65k on it with no sign of splne failure so that seems to be a plus. Luckily I don't HAVE to ride it too much right now, maybe a couple hundred miles per month.

 

Morning thondo

 

(IF) you have an 1150RT then your have the I-ABS (wizzy) system. Some did call it the ABS III system but that was just a nickname.

 

Your brakes are applied by power servos (pumps) & the pump pressure is controlled (modulated) by the amount of brake lever or pedal pressure applied to control pistons on the control (input) side.

 

Your brake system is basically split into two halves-- the control side & the wheel side. It is also bled as separate systems as the control side has no direct hydraulic connection to the wheel side

 

[thondo]

What are the differences between the various systems? Evidently this is a linked servo driven system and I understand that there is a separation between wheel circuits and control circuits. I have to remove the gas tank and right fairing to access the control circuits reservoir (absurd). Is there a simplified block diagram of how this works anywhere? Is the only consequence of running a servo dry having to bleed the system over again? When changing hoses, what are the risks to the system? When bleeding the system, blocking the calipers open is simply to remove as much old fluid as possible correct? Since I am rebuilding this bike after sitting for so long, what is the best way to remove ALL the old fluid since I am changing the lines...I was hoping that by back bleeding I would be able remove all the old fluid by pushing it out without any of the servos being run dry. Is it safe to simply open the system, let the servos run it dry, replace the hoses and refill from there? Sorry for all the questions but I need to understand how a system works, what it is doing and the risks involved before I work on them. Not a fan of blindly following procedures I don't understand reasons for. The posts I have read here are full of good advice on how to do something, not so much on why. So far yours have been a help.

Edited July 11, 2017 by thondo

[dirtrider]

Morning thondo

 

What are the differences between the various systems?--BMW has a number of ABS braking systems so there is no easy way to list the differences between ALL the systems. The main difference between the BMW 1100RT (ABS-2 & the BMW 1150RT (I-ABS) is the 1100 is a straight through ABS system with a piston driven ABS system. The 1150RT system uses servo pumps to apply the brakes & uses servo fluid as ABS dumped make-up fluid.

 

Think of your 1150RT system as having two separate sub systems-- like a little man sitting in the ABS controller box-- your rear brake pedal hooks the the little man's left ear & your front brake lever hooks to the little man's right ear.

 

When you pull the brake lever or step on the brake pedal that puts apply-pressure in the little man's ears. He uses that input pressure from you, the vehicle speed, each wheel speed, the wheel decel rates, the difference in speed between the front & rear wheels to tell the servo pumps how much front & rear brake to apply. Then that pressure is sent to the front & rear brake calipers from the servo pumps. (this is a VERY SIMPLE explanation on how the BMW I-ABS system works)

 

If things go wrong & the system fails then the input pressure (lever or pedal) pushes on the apply piston hard enough to move the pistons & actually manually apply the brakes (very hard & long lever or pedal travel)

 

Evidently this is a linked servo driven system and I understand that there is a separation between wheel circuits and control circuits.---yes, there is no direct HYDRAULIC connection between the lever/pedal inputs & the brake calipers.

 

I have to remove the gas tank and right fairing to access the control circuits reservoir (absurd).------actually you need to remove both side fairings to remove the gas tank. (only takes about 5 minutes once you do it a few times)

 

Is there a simplified block diagram of how this works anywhere? --yes & no, I have a block diagram of the I-ABS system hydraulic circuits but I can't publish them here as they are BMW proprietary so it is both against the law & against the web site policies.

 

Is the only consequence of running a servo dry having to bleed the system over again? --depends on: if just run momentarily dry then re-bled no problems as the servo pumps will quickly re-self bleed. The good part is IF you should run the system low then the internal reservoir fluid level sensors should shut the servo motors down.

 

When changing hoses, what are the risks to the system?--none that I know of other than having to replace the fluid & bleed the system afterwards.

 

When bleeding the system, blocking the calipers open is simply to remove as much old fluid as possible correct?---basically, NO-- most think this but the real reason of blocking the pistons back is so the internal controller reservoirs are re-filled to the correct level when finished.

Think about it-- a person bleeds the brakes & refills the controller reservoirs to the correct level with worn brake pads (caliper piston is now part way out of the bores)--then at a later time installs new brake pads, or just removes a front wheel, that pushes the caliper pistons all the way back in the caliper bores & forces brake fluid up & out of the controller. By filling the reservoir's with the pistons pushed back that maintains correct fluid levels in the controller.

 

Since I am rebuilding this bike after sitting for so long, what is the best way to remove ALL the old fluid since I am changing the lines---most of the fluid will run out when you remove the old lines . The remainder should come out when you flush & bleed the system after line install.

 

 

I was hoping that by back bleeding I would be able remove all the old fluid by pushing it out without any of the servos being run dry.---this won't totally flush the servo pumps & control valves. With key-on & using the servos to move the fluid that will clean & flush the wheel side hydraulics. (I don't know anyone that has tried back bleeding so that could allow some air to remain)--I DO KNOW that bleeding using the servo pumps gets all the air out quickly & without issues.

 

Is it safe to simply open the system, let the servos run it dry, replace the hoses and refill from there?---yes, as long as you flush & bleed after closing the system back up. (DO NOT RUN SERVOS WITH NO FLUID IN THEM)

 

It is a very easy system to work on & understand-- just bleed the control side as a standard brake system at the controller bleed nipples. Then bleed the wheel side using the key-on & using the power servos to move the fluid through that side. (just don't allow the controller reservoirs to run dry-- (use a large tight fitting funnel & rubber stopper or a water bottle & a rubber stopper with a hole drilled through it)

Edited July 11, 2017 by dirtrider

[AndyS]

I have to remove the gas tank and right fairing to access the control circuits reservoir (absurd).

 

Why is it 'absurd'?

 

Is the only consequence of running a servo dry having to bleed the system over again?

No, you can seriously damage internal seals and overheat the internal drive components of the Servo pump.

When changing hoses, what are the risks to the system?

If done correctly, none.

 

When bleeding the system, blocking the calipers open is simply to remove as much old fluid as possible correct?

Not quite. It is also to ensure the system is not overfilled.

 

Since I am rebuilding this bike after sitting for so long, what is the best way to remove ALL the old fluid since I am changing the lines...I was hoping that by back bleeding I would be able remove all the old fluid by pushing it out without any of the servos being run dry. Is it safe to simply open the system, let the servos run it dry, replace the hoses and refill from there?

Not a good way to do it. You DON'T want to run the system dry. Just keep filling the relevant reservoirs with fresh fluid as you pump. Have you seen the online guides that show the use of a funnel screwed into the Servo unit. This acts as a brake fluid feed reservoir to allow you to do less stopping and starting whilst bleeding.

 

[thondo]

The absurdity is a system as critical as brakes that I have to remove my GAS TANK to access.

 

Dirtrider, now I think you can see the reasons a newbie could be confused...2 posts to the same questions, one gives me some straight forward info along with some colorful and cute analogies on how and why the system does what it does. It also includes a sober look at the risks. The other gives due warnings that if I do ANYTHING wrong I am going to fry something. Oh, and contradicts previous advice on how to safely change lines.

 

Basically as long as the reservoir sensors don't fall and keep the servos running while I continually hammer the brake levers with the system dry (sarcasm by the way) I am not likely to break the system by pulling the lines, cleaning the mess, installing the lines, filling, fishing and bleeding correct?

 

It is fairly easy to understand not to continually run a fluid pump servo dry continuously but it is nice to know that completely emptying the fluid will not break them.

 

An additional absurdity (not aimed at you dirtrider) is not publishing a simplified block diagram of something like a brake system. I understand manufacturer preference for dealership maintenance but that is a bit... Absurd :-)

[greiffster]

The absurdity is a system as critical as brakes that I have to remove my GAS TANK to access.

 

Maybe it sounds absurd. But in reality, with the QD fuel connectors, the tanks pops off in less than five minutes. It took me longer to take the plastic off the sides.

 

 

[Shiny Side Up]

The absurdity is a system as critical as brakes that I have to remove my GAS TANK to access.

 

Maybe it sounds absurd. But in reality, with the QD fuel connectors, the tanks pops off in less than five minutes. It took me longer to take the plastic off the sides.

 

They have t have somewhere to stick all the goodies that people want on a motorcycle...

[dirtrider]

The absurdity is a system as critical as brakes that I have to remove my GAS TANK to access.

 

Dirtrider, now I think you can see the reasons a newbie could be confused...2 posts to the same questions, one gives me some straight forward info along with some colorful and cute analogies on how and why the system does what it does. It also includes a sober look at the risks. The other gives due warnings that if I do ANYTHING wrong I am going to fry something. Oh, and contradicts previous advice on how to safely change lines.

 

Basically as long as the reservoir sensors don't fall and keep the servos running while I continually hammer the brake levers with the system dry (sarcasm by the way) I am not likely to break the system by pulling the lines, cleaning the mess, installing the lines, filling, fishing and bleeding correct?

 

It is fairly easy to understand not to continually run a fluid pump servo dry continuously but it is nice to know that completely emptying the fluid will not break them.

 

An additional absurdity (not aimed at you dirtrider) is not publishing a simplified block diagram of something like a brake system. I understand manufacturer preference for dealership maintenance but that is a bit... Absurd :-)

 

Afternoon thondo

 

It's REALLY not that complicated. Hundreds or (probably even thousands) of riders & home mechanics bleed these I-ABS brakes every year & seldom do you hear of any problems.

 

Below is the bleed sequence for the control side when you get that far (use the original bleed process after a line change)

 

[dirtrider]

Afternoon thondo

 

Thing to keep in mind when working on the BMW 1150 boxer bike is to try & combine operations that require the same general prep (like removing Tupperware or removing fuel tank)

 

Like now, when you have the tank removed for brake work, is a VERY GOOD time to also replace some of the in-tank hoses & fuel filter (especially the U shaped hose). That U shaped high pressure hose inside the fuel tank is failure prone on older 1100/1150 bikes & will leave you walking DRT (Dead Right There)

 

If you get into the habit of combining operations then removing the fuel tank & Tupperware doesn't seem so extreme to do service.

 

Just be glad your BMW 1150 isn't a BMW 800 twin as the cams have to be removed to do a simple valve adjustment.

 

Also remember that we are here so you can always do one brake part at a time then we can talk you through the next part as you get to it.

[greiffster]

It's REALLY not that complicated. Hundreds or (probably even thousands) of riders & home mechanics bleed these I-ABS brakes every year & seldom do you hear of any problems.

Yup. I did mine every year. Not hard, but I always made a mess.

 

They have t have somewhere to stick all the goodies that people want on a motorcycle...

 

You might have a problem trying to find folks willing call the I-ABS (whizzy) system a "goodie", but point taken.

 

I remember my early 90's Buick Regal with the transverse V6. You had to loosen the engine mounts and "rotate" the motor forward to gain access to the three spark plugs against the firewall, and then it was still a PITA. And I would probably call spark plugs more "essential" than a "goodie".

 

Ease of access to maintenance items on cars, boats, motorcycles (at least of all mine) seems to be a low priority for the design engineers. Probably been that way for a long time.

 

I laugh every time I pop the hood on my wife's supercharged Mini Cooper. Talk about 10 pounds of crap in a 5 pound bag.....

 

[thondo]

Sounds like good advice...I am already hating taking the plastic of... Already broke one tab fitting it back on and I found out that the tank shrinks slightly with age making the screw holes misalign slightly with the inserts in the tank. This job is not terribly difficult, just a pita that might have been made better by a different mindset in engineering. Considering I work for an engineering firm, I notice when maintainability is made a priority. I love both my bmws but anyone who has ever worked on a Honda then a BMW can tell the difference in mindsets.

 

This job does not seem fun for 1 person.

 

Grumble grumble.

[greiffster]

Sounds like good advice...I am already hating taking the plastic of... Already broke one tab fitting it back on and I found out that the tank shrinks slightly with age making the screw holes misalign slightly with the inserts in the tank. This job is not terribly difficult, just a pita that might have been made better by a different mindset in engineering. Considering I work for an engineering firm, I notice when maintainability is made a priority. I love both my bmws but anyone who has ever worked on a Honda then a BMW can tell the difference in mindsets.

This job does not seem fun for 1 person.

 

Grumble grumble.

thondo,

Leave the main tank bolt a little loose when you first put the plastic back on after removing the tank. There is a little play or wiggle in the tank and it's easier to line up the fairing holes.

 

 

[dirtrider]

Evening thondo]

 

Already broke one tab fitting it back on and I found out that the tank shrinks slightly with age making the screw holes misalign slightly with the inserts in the tank. --Just put the panels out in the hot sun for a few minutes then the screw holes usually line right up with a little wiggling. -- OR, use a small needle file or Dremel to slightly slot the screw holes.

 

This job is not terribly difficult, just a pita that might have been made better by a different mindset in engineering. Considering I work for an engineering firm, I notice when maintainability is made a priority. I love both my bmws but anyone who has ever worked on a Honda then a BMW can tell the difference in mindsets.--It's all about the money & manpower. No motor company designs for service or maintenance any more (been like that for years now). Number one is usually looks (showroom appeal or magazine article appeal) & number two design criteria is usually for quick assembly and/or ease of assembly with less manpower per assembly event.

 

Most vehicles are assembled from sub assemblies so in the case of the 1150RT BMW the brake controller & lines are hung on the sub-assembly way before the fuel tank is mated to the bike.

 

If you think a simple brake flush is bad just wait until you have to install a clutch or alternator.

 

 

[Lowndes]

"If you think a simple brake flush is bad just wait until you have to install a clutch or alternator." By DirtRider.

 

TRUE WORDS, thondo. They start assembly with an alternator and build the rest of the bike around it.

 

Thankfully there is a shortcut to the clutch. Kinda.

 

"Everything is relative."

[AndyS]

The absurdity is a system as critical as brakes that I have to remove my GAS TANK to access.

Why is it absurd? you need to get the covers off to do a full service, so just include this brake system maintenance at the same time. Getting the covers off and on is really no big deal if it is done correctly.

 

now I think you can see the reasons a newbie could be confused...2 posts to the same questions, one gives me some straight forward info along with some colorful and cute analogies on how and why the system does what it does. It also includes a sober look at the risks. The other gives due warnings that if I do ANYTHING wrong I am going to fry something. Oh, and contradicts previous advice on how to safely change lines.

Again no contradiction, just building a picture. So like learning anything, the information is laid out in different ways so that it builds layers of understanding.

 

It is fairly easy to understand not to continually run a fluid pump servo dry continuously but it is nice to know that completely emptying the fluid will not break them.

Why run it dry at all? Just drain out the tubes, Suck out what fluid you can from the reservoirs with something like a meat baster, then refill and flush with brand new brake fluid.

 

is not publishing a simplified block diagram of something like a brake system. I understand manufacturer preference for dealership maintenance but that is a bit... Absurd :-)

Sorry thondo, I am not getting what you are bemoaning here. There is SO MUCH info about this system. Probably too much as it tends to start confusing and instilling fear into operators (as seems to be the case here). The owners manual AND the workshop manual commits an amazing amount of space to this system.

Have you seen the threads such as these that show just how simple this job is?:

http://bmwsporttouring.com/ubbthreads/ubbthreads.php?ubb=showflat&Number=10156

[thondo]

I am going to be looking for info on that shortcut to the clutch within the next year. Collecting parts and supplies for that job now. I just got back from my job site and have the weekend to figure out changing those lines... But I would rather play with my 2 year old... But it has to get done. Hopefully I won't make too big a mess. Do you always have to do the abs reset procedure after something like this?

 

Any advise on re covering the wiring harness?

[thondo]

What are the difference in the brakes between the 2002 r1150rt and the 2002 k1200rs.

[thondo]

Ok, you talked me into it. Pulled the Tupperware, drained the system, changed hoses, bled system. I think I got it largely correct...

 

But I don't know for sure because I can't start my bike. Broke a fuel line quick disconnect on disassembly and didn't notice until I began reassembly.

 

FML

[Alan Sykes]

If you stare fixedly at the various sections of footage on the BMW.tv site with all the assembly-line videos showing how they put boxer motorcycles together in Berlin-Spandau, you can clearly see that they do the initial load-up or charging of the the brake hydraulics pipework backwards up from the nipples - and from the ABS control unit / modulator.

 

So it's not too far a stretch of imagination to assume that raplacement fluid can be injected in the same manner at a service interval, assuming one has the correct gear to squirt the juice into the system under pressure, flirting out the old mucky juice and following it airlessly with new DOT4.

[thondo]

Dirtrider... Any insight on the info from Mr. Sykes? At this point I am interested in the possibility, safety, and mechanics of backfilling since I have now done the regular procedure... Not including breaking my fuel fitting.

[Michaelr11]

Thondo - it's not very hard to back fill. I did it on a friends RT after he installed new Speigler brake lines. Got a syringe from the farm supply store (for animal meds) and attached some clear soft tubing to the end. Filled the syringe with DOT4 brake fluid, attached the clear hose to the end of the brake bleeder on the caliper. Open the bleeder and open the master cylinder reservoir. Push down on the syringe and force the DOT4 into the brake caliper through the bleeder. It will fill the entire line and ABS.

 

Sorry - my description above is for the R1100/ABS2 which is one circuit for front and one for the rear. The 1150 would be back filled from the caliper to the ABS bleeder. Then, back fill from the other ABS bleeder to the master cylinder. Each circuit done separately.

[dirtrider]

Dirtrider... Any insight on the info from Mr. Sykes? At this point I am interested in the possibility, safety, and mechanics of backfilling since I have now done the regular procedure... Not including breaking my fuel fitting.

 

Morning thondo

 

Could you back fill or back flush?--Sure

 

But WHY, that isn't the way the service work is done, I see no gain in doing the BMW I-ABS system that way.

 

You want to run the servo pumps to flush & bleed the wheel circuit side.

 

Back flushing with enough flow & pressure is a sure way to blow paint eating brake fluid all over your paint & plastic.

 

If there was something to gain by back flushing then it would be in the service procedure as well as every shop would be doing it that way.

 

 

 

[thondo]

Ok, the job is finally complete. I got home this weekend, replaced the fuel lines and quick disconnects with the chrome plated brass ones from beemer boneyard. Put it all back together and rode it for 50 miles. No blinking lights, no puddles of fluid, no failing brakes. Seems like I managed. There are things I learned. It won't be such a big deal next round.

 

Dirtrider - as I said, since I have already done it the "right" way now, it is an intellectual exercise of learning if something can be done differently and why you would or would not do that. As for things not being done that way in shops, there are hundreds of things that for various reasons (usually tools or equipment) that are done differently by home mechanics than shop technicians. In this case, I can certainly see your logic and having done it, I can understand that backfilling would not really change the difficulty of the procedure since the most complicated part is removing the tupperware and tank which you would have to do anyway. In that case, no reason not to use the servos. But now I know that it would not damage the system and I have a better understanding of how the system works, regardless of fluid flow direction. I am still not 100% sure if it could possibly damage that near irreplaceable abs pump though.

[thondo]

One question I have. Front left caliper line seems a bit twisted (as was the stock part) with some tension put on the solid line there. Since I am going to have to replace the rubber vibration grommet there anyway (and bleed again) are there any suggestions on removing some of the stress from the lines in this location?