1150 adv ABS woes- no come back, need help ............
- Thread starter Ed209
- Start date
Get the fault rectified and find yourself with next to feck all braking at a random point when riding, or remove and ride in the knowledge that you don't have abs but the brakes will always work. I know which one makes more sense to me.
servo brakes, so shit even BM weren't so arrogant as to carry on with them
servo brakes, so shit even BM weren't so arrogant as to carry on with them
ahutcheon
Registered user
I'll offer the counter that my servo brakes haven't failed/killed me in 70,000 miles and I have been very glad of the abs once. But if the servo does fail and I live through the experience I'll be throwing it away rather than throwing big money at it...
It will happen, but when is anyone's guess.
Had servo brakes on BMW bikes since 20001, never failed me yet and ABS has been a godsend on at least a couple of occasions. Many people advocating the removal are just repeating what they have heard other say or do. agreed some people have had problems but there are a much greater number of people that are pleased with the servo brakes and never had any problems. More people have had brakes on the GS fail because of faulty front hoses, very common and you then don't even have residual braking.
You have a brake fault, repair it, if you can't get someone who can, its what you would do on you car..
You have a brake fault, repair it, if you can't get someone who can, its what you would do on you car..
Ed209
Registered user
I can repair it but im trying to work out how the whole system works as it may be as simple as the brake light swich. Just need to know where the servo unit gets its signal from whether its the pressure from the rear cylinder and or the signal from the brake light switch. I can do the servoectomy but need the bike on the road for now hence why I wanna know how the system works 
The Grey One
Registered user
I can repair it but im trying to work out how the whole system works as it may be as simple as the brake light swich. Just need to know where the servo unit gets its signal from whether its the pressure from the rear cylinder and or the signal from the brake light switch. I can do the servoectomy but need the bike on the road for now hence why I wanna know how the system works
It's the switch.
John
Servo ABS switches are normally closed (contacts made)
Once you operate a lever it breaks the contact and the ECU starts the servo motor whirring ....(and switches on the brake lamp)..
The AbS block unit merely amplifies the input energy from your hand / foot to the calipers
If a wheel falls below a graph line of "maximum acceptable rate of deceleration" from the programming
it initiates the wheel unblock until it passes back above the line and initiates again if the value is exceeded for any given road speed
Hopefully that made sense to You ??
BE warned there are 4 reservoirs !!!! You bleed the hand / foot levers AT the ABS block
and you bleed from the ABS block to the calipers
If you try to bleed straight through from Master cylinder to Caliper?
You cant and you will find that the servo assembly is fcuked after about 30 seconds running with no fluid!
Once you operate a lever it breaks the contact and the ECU starts the servo motor whirring ....(and switches on the brake lamp)..
The AbS block unit merely amplifies the input energy from your hand / foot to the calipers
If a wheel falls below a graph line of "maximum acceptable rate of deceleration" from the programming
it initiates the wheel unblock until it passes back above the line and initiates again if the value is exceeded for any given road speed
Hopefully that made sense to You ??
BE warned there are 4 reservoirs !!!! You bleed the hand / foot levers AT the ABS block
and you bleed from the ABS block to the calipers
If you try to bleed straight through from Master cylinder to Caliper?
You cant and you will find that the servo assembly is fcuked after about 30 seconds running with no fluid!
ahutcheon
Registered user
To digress from the good Doctor's fine advice, there are a couple of perfectly normal behaviours of the servo brakes that can freak you out when you first meet them:
The anti-stoppie function can let off the front brake if it can't get the rear spinning again by releasing it. Braking through dips in the road surface downhill can invoke this, badly corrugated approaches to downhill hairpins on unsealed roads can be hilarious.
After a short while holding the bike stationary on the back brake the servo will switch to a power save mode. If you're on a hill, the bike will move about 2cm but it feels like half a bike length the first time it happens.
The anti-stoppie function can let off the front brake if it can't get the rear spinning again by releasing it. Braking through dips in the road surface downhill can invoke this, badly corrugated approaches to downhill hairpins on unsealed roads can be hilarious.
After a short while holding the bike stationary on the back brake the servo will switch to a power save mode. If you're on a hill, the bike will move about 2cm but it feels like half a bike length the first time it happens.
Bendy toy
Registered user
There is info on You Tube for replacing the servo/ABS motor brushes. After the sort of miles many 1150s have done it could simply(?) need new carbon brushes in the motor.
Ed209
Registered user
I can hear the microswitch working and the brake light operates but there is no servo whine? Does that mean the switch is ok but the servo has a problem?
The servo works fine for the front brakes but not the back. i get the warning lamps whether I use front or back break
The servo works fine for the front brakes but not the back. i get the warning lamps whether I use front or back break
Because they are a linked system
Either go get it plugged in and diagnosed and stop going around in circles
Or de-servo it
If they haven't had VERY regular fluid changes then the fluid could be original
Plungers could be stuck
the rear plunger could be burned out
The ECU could be toast on the rear circuit
# check this link for sticking plungers
Not sure if you've seen this but this is the list of fault codes from the lights for iABS but to be sure and as previously suggested you can always take it to a dealer and they'll plug it in and give you the answer in 5 mins:
http://www.largiader.com/abs/absfault.html
Incidentally the same thing happened to me on day 1 of a french trip last year (rear break circuit failed to residual braking on '04 1150GSA). Did a bit of poking around and realised that it was ok to continue but if it had been the front then that would have been a different story. Got home and removed the servo and solved the problem. If it is of any use, I also got the front calipers overhauled (seals etc) and now there is a lot more feel than before and it also feels like it would tear the tarmac from the road if the anchors were deployed in anger as were.
Ed209
Registered user
Hi mate, yeah i found the list of codes and although didnt go that route, its the rear system at fault. Decided on the servoectomy and ripped it all out yesterday Just got the electrics to do using the original relay then bleed. Hope I get brakes lol.
I took pics but didnt know how to put them up but its been shown before so dont think theres any need.
I took pics but didnt know how to put them up but its been shown before so dont think theres any need.
That only applies to the later 1200 abs. Nothing relevant to the 1150 versions.
Please don't say you've used the completely unnecessary "cut the wiring" method
Bendy toy
Registered user
Presumably the 1150 ABS has a motor which should have carbon brushes. So the 1200 instructions should show in principle what's needed
Its a totally different system Bendy
The 06 on 1200 system uses a much bigger motor and it is that unit that needs brushes
The earlier Servo systems has issues with swelling seals and plunger o rings jamming and causing failures "usually" due to negligence in servicing i.e. Wheel circuits fluid change = annual Control circuits fluid change = bi annual
Me? I change all the brake fluid every year end of story !!
Presumption - the mother of all feck-ups.
Ed209
Registered user
Well yeah I cut the required wires from the abs plug loom and wired them to the old abs relay as per dave h instructions? I thought that's the way everyone was doing it? If it's wrong why is everyone linking to it as de riguer ? Done now. If I just unplugged the abs plug and taped it up do the tail and stop lights still work fine?
No you have to separate the pump and electronic bits
and isolate the pump power wire and remove ABS bulbs in dash
Leaving the ABS control unit plugged in makes the lights work (and to send info to the speedo on K series and R1200C and Roxsters i think )
and isolate the pump power wire and remove ABS bulbs in dash
Leaving the ABS control unit plugged in makes the lights work (and to send info to the speedo on K series and R1200C and Roxsters i think )
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