05 Low Brake Fluid

[Tech1]

My 05 suddenly had the brake failure light flashing.  Plugged in a gs911, had codes for low front brake pressure too low (24970) and brake fluid level too low (25193), the brakes still worked fine.  Standard front and rear reservoir levels were ok, so I took a look at the abs unit; the front chamber level was fine but the rear chamber level was definitely low.  I figured that maybe I didn't properly get the air purged and level set on the rear circuit when I flushed the abs a couple years ago and after the pads wore, the level dropped.  I know you should push the pads in before setting the level, but I was a bit impatient and just filled it to the normal level, figuring I would deal with it at the next pad replacement.  All seemed fine, no more warnings.  Now I notice what looks like brake fluid on the floor near the center stand, after sitting a day, after about a 100 mile ride.  I should note that earlier I did do an oil change earlier this season and shortly after I had what I thought at the time was a bit of an oil drip in the same location, I figured I just didn't get something wiped up from around the filter.  Now I am not so sure, thinking that it was probably brake fluid, likely dripping from the overflow.  Thoughts on what could push the fluid out the overflow?

[dirtrider]

7 hours ago, Tech1 said:

My 05 suddenly had the brake failure light flashing.  Plugged in a gs911, had codes for low front brake pressure too low (24970) and brake fluid level too low (25193), the brakes still worked fine.  Standard front and rear reservoir levels were ok, so I took a look at the abs unit; the front chamber level was fine but the rear chamber level was definitely low.  I figured that maybe I didn't properly get the air purged and level set on the rear circuit when I flushed the abs a couple years ago and after the pads wore, the level dropped.  I know you should push the pads in before setting the level, but I was a bit impatient and just filled it to the normal level, figuring I would deal with it at the next pad replacement.  All seemed fine, no more warnings.  Now I notice what looks like brake fluid on the floor near the center stand, after sitting a day, after about a 100 mile ride.  I should note that earlier I did do an oil change earlier this season and shortly after I had what I thought at the time was a bit of an oil drip in the same location, I figured I just didn't get something wiped up from around the filter.  Now I am not so sure, thinking that it was probably brake fluid, likely dripping from the overflow.  Thoughts on what could push the fluid out the overflow?

Morning  Tech1

 

Thoughts on what could push the fluid out the overflow?-- Usual cause is overfilling the module reserviour with worn brake pads, then when barke pads are pushed back it kicks excess fluid out of the reservoir vent.

 

Or, sometimes they will kick a little fluid out of the ABS module vent if the motorcycle  is laid on it's side for  while. 

 

If the ABS module is kicking fluid out the vent for no reason & you haven't overheated & boiled the brake fluid (fluid that contained moisture)  then I really don't know what caused it. 

 

Is it possible that the fluid is not leaking out the event but leaking from a line or fitting??? 

[Tech1]

It stopped coming out the overflow "again?" and I don't have any warnings.  I will ride for a while and see what happens.  I guess I could understand if I happened to overfill it this time in my haste.  Still I didn't do anything with the pads, so why did it start coming out the overflow about 2 years after it was flushed and end up low?

I have been trying to come up with reasons to buy a new shiftcam, I guess.  The potential issues on the brakes, and now I found a crack starting on one throttle cam, maybe it is time!   Thanks for the input.

[dirtrider]

10 hours ago, Tech1 said:

It stopped coming out the overflow "again?" and I don't have any warnings.  I will ride for a while and see what happens.  I guess I could understand if I happened to overfill it this time in my haste.  Still I didn't do anything with the pads, so why did it start coming out the overflow about 2 years after it was flushed and end up low?

I have been trying to come up with reasons to buy a new shiftcam, I guess.  The potential issues on the brakes, and now I found a crack starting on one throttle cam, maybe it is time!   Thanks for the input.

Morning  Tech1

 

Has the motorcycle been over on it's side recently? That can allow fluid onto the vent. 

 

Is the rear wheel crown bearing loose? That can allow the brake rotor to kick the brake pads back.

 

Possible but not likely, there could have been A LOT of moisture in the rear brake fluid,  then using the brakes hard & continuous could have boiled the fluid causing the moisture to turn into steam & expand therefore pushing fluid out. (again unlikely)  

 

 

[Tech1]

It hasn't been on it's side in a few years!  I am going to look up when if the rear flange recall was done before or after I did the brake flush and I will do a good check on the crown bearing.  Thanks for pointing out the things to check.

[dirtrider]

39 minutes ago, Tech1 said:

It hasn't been on it's side in a few years!  I am going to look up when if the rear flange recall was done before or after I did the brake flush and I will do a good check on the crown bearing.  Thanks for pointing out the things to check.

Afternoon Tech1

 

They probably pushed the rear brake pads back when they did the rear flange recall. (this could explain  the fluid in the vent line)

 

But that doesn't explain how the rear reservoir went low. (make sure you don't have a seeping line or connection)

[Tech1]

Went for an 80 mile back roads ride, parked it on the center stand, one tiny drop of something on a paper towel underneath.  Brakes feel fine.  Going to ride a bit longer, hate to waste the great weather we have here right now.  I will tear into it a bit when it is more convenient, unless something pushes me into doing something sooner.  At least I don't have any long distance rides planned this year.

[Tech1]

An update, probably not good news.  Low brake fluid and pressure warning again.  Top off the rear pump and cycle the brakes a few times, the dual flash warning goes away. Leak may be getting worse and it is "not" from the overflow hose.  It appears to be from the bottom of the ABS/Pump unit, leaking down around the cases and some of the fluid even drips on top of the exhaust.  So I will have to see what it takes to remove the ABS unit to investigate further.  I hear the cost is prohibitive on the oem replacement and Module Master service is not available for this model, some question if it will ever be.  Maybe I can get lucky and what ever is leaking is an easy fix, but I have done a little investigation into removing the ABS unit, keeping the circuit board connections to keep the brake light and speedo functions working.  I don't know if it keeps the computer fault system happy, more investigation to do on that.  Maybe someone here is familiar with the mods and knows.  I know there is something offered in Germany to make everything happy, it looks like it even keeps the line connections in the same locations so you can just swap everything out,  but reports are that it is still a little costly and there can be issues with shipping.

I guess I have some work to do!  If anyone has some suggestions or insights about it, let's hear it!

By the way, during my investigation, I couldn't feel any play in the crown bearing.  Just to be sure, I did drop the complete final drive.  It rolls smooth, although there is a faint scraping sound, almost sounds or feels like a dry seal.  Hard to believe it is a bearing, it rotates too smooth.  The input, driveshaft splines, and driveshaft look very good.

[lkraus]

Modulemaster has been making servo repairs for a year or so, but still has a backlog of work. Email or call for current status on repairs. https://modulemaster.com/rebuilds/shop/motor-sports/abs-modules-motor-sports/abs-fte-abs3/

 

RH Electronics in Germany has been offering repairs for several years: https://rhelectronics.de/reparatur/geraet/motorrad/abs-motorrad-am/type-am1/#tab-additional_information

 

RH Electronics also offers a bypass kit to remove the ABS while retaining speedometer, brake light, etc. https://shop.rhelectronics.de/shop/produkt/motorcycle/new-equipment-en/rh-second-life-kit-can-2/?lang=en

[Tech1]

I checked modulemaster's website earlier, and your link confirms nothing changed, it says "currently under development, not available at this time".  I will give them a call, maybe their website isn't current.  As for RH Electronics repairing mine, I am not really interested in sending mine overseas, and the price is still very expensive.  Regarding the RH bypass kit, it pretty much does everything I can do except for a couple of nice touches:  it looks like it may let you plug your normal line connections into a ported bracket without the need to replace or rework the front and rear brake line connections, and it sounds like it does something about the software issues so there are no warning lights.  On the 05 RT, the info I have says that if you can keep the module circuit board/housing, the brake light and speedo should function.

 

Of course I would prefer to keep it correct, but on a bike with the current value so low, I cannot justify the expense.  Reports are that the direct connection part works well with good feel, some say better than original, but no abs function.  Too bad bmw doesn't make a kit to upgrade it to the newer non-assist abs, I would consider spending more if it were an actual upgrade that maybe improved the value of the bike some.

 

Thanks for the info, I think I should get out in the garage and take it apart!

 

Gary