Quick question please, about to flush brake fluid completely, when it comes to the abs unit itself will it flush just pumping brake levers or does it need a vacuum to drag the fluid out?? ..... Cheers 
Brake fluid flush 1999 BMW R1100RT non servo
- Thread starter Mark H
- Start date
Just pump from the Master cylinders to the ABS Unit
On the ABS unit you will see VR and HR stamped beside a bleed nipple each
HR = Hinter Rad or Rear Wheel
VR = VorderRad or Front wheel
Flush the fluid out of the respective nipple until you have fresh fluid and then on down to the respective calliper (s)
On the ABS unit you will see VR and HR stamped beside a bleed nipple each
HR = Hinter Rad or Rear Wheel
VR = VorderRad or Front wheel
Flush the fluid out of the respective nipple until you have fresh fluid and then on down to the respective calliper (s)
Just bleed the brakes until the new clear brake fluid comes through. Doesn't need any vacuum or fancy gear. There are 2 bleed nipples on top of the abs unit, but conventional bleeding will do. Saves removing the tank and fairing too.
If it hasn;t been changed in a long while it is advisable to flush at the unit to get "all" of the contaminated stuff out
Thanks all, it has not been flushed since ss lines were fitted in 2012, then it was only master cyl to calipers, did not flush abs unit, now have an abs fault with lights flashing, its been doing this since last august when battery failed, I can clear it with a reset and it lasts a while but keeps coming back, hoping a full flush will sort it. 
Thanks all, it has not been flushed since ss lines were fitted in 2012, then it was only master cyl to calipers, did not flush abs unit, now have an abs fault with lights flashing, its been doing this since last august when battery failed, I can clear it with a reset and it lasts a while but keeps coming back, hoping a full flush will sort it.
You should check the fault codes
AND check your ABS rings are not very rusty and the Air gaps are correct
If it happens just after a start up its the Low voltage warning
If it happens when you go over a certain speed every time its likely the ABS rings need a clean or the air gap needs checked
The fault started when the battery failed last August, it was fine up to then, a new battery was fitted, and ever since the lights have flashed, the new battery is not faulty and is fully charged, the abs rings are fine, everything was fine till the battery failed, I can do a reset and it cures it , till next time I ride, the battery is on a ctek charger when not using and shows the battery fully charged,
I'm half way through a brake fluid flush and the fluid out of the abs unit was quite dark (Dirty) particularly the rear brake part, yet to do calipers, the bikes having a big service and I'm waiting for parts and tyres so wont be testing for a week or so.
Somebody on another forum said not to touch the abs unit and just flush through from master cylinders to caliper? is this correct? if so whys the abs unit got bleed nipples?
I've done it anyway
All Done! was pretty dirty, especially from the rear circuit ... all the dirt settled to bottom
Dirty brake fluid by Mark Handley, on Flickr
Dirty brake fluid by Mark Handley, on Flickr
Meh!! Thats not Dirty
This is Dirty
On the left First Flush
On the right THIRD Flush
and it got a 4th one!!! It took a litre to clear out all
This is Dirty
On the left First Flush
On the right THIRD Flush
and it got a 4th one!!! It took a litre to clear out all
Flushing/changing the brake fluid won’t change a thing (apart from the fluid) - the flashing lights on the pre-servo system are nothing to do with fluid, any fault warnings are purely electrical or pistons in the modulator decked.Thanks all, it has not been flushed since ss lines were fitted in 2012, then it was only master cyl to calipers, did not flush abs unit, now have an abs fault with lights flashing, its been doing this since last august when battery failed, I can clear it with a reset and it lasts a while but keeps coming back, hoping a full flush will sort it.
Michael R1150GS Adventure
Registered user
Hi - does that mean I can flush the fluid through the whole system by just bleeding at the 3 callipers?
Probably not!
But there is no way of answering your question. You haven’t told us what bike you have.
They do not have all the same brake systems.
Michael R1150GS Adventure
Registered user
Probably not!
But there is no way of answering your question. You haven’t told us what bike you have.
They do not have all the same brake systems.
2003 twin spark servo abs
Then definitely No.
Your bike has 4 seperate brake systems.
Front and rear control circuits which are bled conventionally from their reservoir to the servo unit (under fuel tank).
Front and rear power circuits which are power bled from their reservoirs located on the servo unit to their respective caliper.
Read this.http://users.rcn.com/dehager/service/service_abs3.pdf
It ‘s long winded, but will help you understand what is needed to bleed you brakes, and the technique required. If you feel this service is not for you, then find someone who can.
Michael R1150GS Adventure
Registered user
I'll be fine doing that - thanks for direction to that link
Closure on this abs flashing fault, it was a slack alternator belt, spinning alternator enough to keep gen light out but slipping, readusted belt, reset abs and done 500 miles nor with no lights flashing and abs arming normally
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