Servo/ABS problems

Gordon · Mar 14, 2008

Help please!!

1150 GS 2002 ABS and Servo. Ignition switched on and self checking starts.
1.Lower brake warning triangle light stays on
2.Upper brake failure light flashes rapidly, servo whines, light slows momentarily then flashes rapidly again (forever)
3. Pressing front lever triggers servo and rear brake light
4. Pressing rear lever does not trigger servo but brake light comes on.
5. ABS relay in fuse box ticking in time to rapidly flashing brake failure light

So far - checked:
1. Rear brake light switch - working fine
2. Fluid levels in both brake reservoirs and in the servo reservoirs - all fine
3. Levers not hampered in movement e.g. not hitting hand guards
4. Battery fully charged and starting bike
5. Taken bike for 20 mile run - front brake fine. Rear brake - residual braking only
6. Ordered a new ABS relay (at £6) - don't know if this will solve problem

Don't know whether resetting ABS will do any good but all instructions I can find are for non-servo model with a brown-blue wire (at number 2 pin). My diagnostic plug is blanked at No 2 and has no brown/blue wire.

Is it time to get to a dealer????

Carl · Mar 14, 2008

Gordon said:
Is it time to get to a dealer????

Yes, get the fault codes read.

AFAIK the reset procedure is only for the non-servo ABS bikes.

Steptoe · Mar 14, 2008

Gordon said:
Don't know whether resetting ABS will do any good .

It's not the ABS thats the problem. It's the servo.

f800gs · Mar 14, 2008

This must be fiction. From what I've read here, only the 1200 has faults like this. :augie

mermoto · Mar 14, 2008

iABS fault codes

• Gen OFF, ABS ON = Only residual braking in both circuits.
• Gen OFF, ABS flashes at 1Hz = ABS not available. Pull-away test not completed.
• Gen OFF, ABS flashes at 4Hz = Only residual braking function available in both circuits.
• Gen ON, ABS off = rear light/brake light defective.
• Gen ON, ABS flashes at 1 Hz = At least one brake circuit without ABS.
• Gen ON, ABS flashes at 4Hz =At least one brake circuit in residual braking function mode.
• Gen AND ABS flashing alternately at 1Hz = Fluid level in Intergral ABS too low.Low-voltage

Mermoto

ELIMINATOR · Mar 14, 2008

It's not the ABS thats the problem. It's the servo.

Oh shit, time for a servoectomy then?

Gordon · Mar 14, 2008

Gen ON, ABS flashes at 4Hz =At least one brake circuit in residual braking function mode.

This is the one.

It's not the ABS thats the problem. It's the servo.

Oh shit, time for a servoectomy then?

Ok, so looking serious. What are my options? A trip into the country with a box of matches?

ELIMINATOR · Mar 15, 2008

Someone on this site has binned the servo, and connected up brake lines direct to the master cylinder. You'll need an inline banjo bolt brake switch as well.

Plus either remove the relay for the servo??????? or remove the bulbs for the warning lights.

http://www.ukgser.com/forums/showthread.php?t=108423&highlight=servo+removal

Gordon · Mar 15, 2008

Thanks, Eliminator.

Made the decision yesterday to bin the servo and started work on this today. Back brake caliper now connected directly to rear master cylinder, bled and working a treat. I will order the brake switches and 'splitter' on Monday and complete the hydralics on the front brake next week. I have run in some wiring to the fuse box and rear stop light ready to link up the switches. Servo will lift out creating a lovery free space and a few kgs of weight.

Would rather have had ABS but feel that I will have a simple and more reliable braking system and avoided spending £1400 on something that might go wrong again.

Cheers

ELIMINATOR · Mar 15, 2008

My servo is the third one fitted to the bike.

1) Whilst within warrantee

I started up as usual, rode the 50' to the junction, NO BRAKES

No warning lights

until it eventually stopped :confused:

Bike picked up by SPC.

2) Six weeks later, see 1) :spitfire

Took some time to regain any faith

now on 38,000 miles. Be interesting to see how much this has cost you, both in time & money. Might be good idea as Steptoe said, to remove servo & sell it on.

Gordon · Mar 17, 2008

Be interesting to see how much this has cost you, both in time & money

.

Switches are £23 and £20 and front brake pipe connector is £46 so the whole lot is £89 exc postage. Ordered today from Motorworks so expect parts by Wed/Thurs. Have used existing brake pipes and hoses.

Time so far: Rear brake hydraulics took 30 mins to complete. Running wire to rear brake light took 25 mins (removed tool tray and fed new wire into loom and connected to rear stop light spade). Removed of existing brake switches took a further 30-40 mins. All done at a leisurely pace.

Should see job completed in 1-2 hrs (famous last words)

Cheers

SoFTSTuFF · Mar 17, 2008

Love to see some pics and a ride report at the end :clap

This something i like to do on my 2005 adventure as wel...

Bye Jan Willem

Gordon · Mar 21, 2008

Love to see some pics and a ride report at the end

Well, job done and much thanks to Delpel for his thread and pics. How I did it for my bike was as follows:

Preparation. Make sure that you have all of the parts you need or (like me) order them as you go along. The parts I needed were:
a. Conventional front brake switch (non-ABS)
b. Conventional rear brake switch (non ABS)
c. Front hydraulic brake distribution unit (union) (non ABS)
d. DOT 4 Brake fluid
e. Brake bleeding kit
f. Wiring, connectors, soldering iron and solder
g. Circuit tester
h. Big bag of tools

Total cost of BMW parts was £89 and got these from Motorworks. Have your chassis number when you call.

Wiring etc cost about £8 from Maplin. Rest I already had.

I removed the seat, petrol tank and tool box in order to get ready access to wiring looms.

1. Rear Brake Hydraulics. This was simple. I disconnected the rear pipe and connected it directly onto the master cylinder. Bled the brakes and that was it - job done (pic 1)
2. Next step was to remove the rear brake switch which is situated behind the RH footpeg (pic 2)
3. The front brake switch also needs to be removed from beneath the RH grip (pic3)
4. Eventually (but not yet) the faulty unit will be removed (pic 4)
5. And this distribution piece will be replaced with a non ABS part (pic 5) - to be continued

delpel · Mar 21, 2008

Glad to be off assitance chap :beerjug:

Gordon · Mar 21, 2008

Next Steps:

Brake switches arrived first so dealt with these. These were exacly the same shape and size as those that had been removed so fitting them was a reversal of removing the old ones. The tricky bit was wiring them up. I opened up the fuse box (undoing 4 screws gives access to the wiring looms)and wired both switches up as non ABS switches using the wiring diagrams in the Haynes manual. I also did this for the tail light (different fuse). This involved running some new wiring and making some connections but nothing complicated. Pic 1 contains 1 = Non ABS front brake hydraulic distribution unit with bleed nipple added -nipple MUST be ordered as a separate item. 2 = rear brake light switch. 3 = front brake light switch.

Pic 2 - still there but not for long!!

Once electrics were done and tested it was time to focus on fitting the front brake distribution unit. (pic 3) This was straightforward and the master cylinder pipe fitted onto the upper part of the unit and the feed to both calipers onto the lower part. The bleed screw was fitted to the upright part. Once everything was in place and tightened the brakes were bled.

Should have said earlier that a 'best buy' at my local Makro was a bike lift - great buy at £40. Pic 4

By now the job was essentially done but some tidying up was needed. All redundant pipework was removed. The fault unit was upplugged and the retaining bolts at the bottom of the unit removed. The big electrical plug was uncoupled and the whole unit removed leaving a big space - (pic 5). Care should be taken to catch spills of brake fluid duuing this and earlier hydraulic work.

Gordon · Mar 21, 2008

And finally.

Both brakes feel firm and all electrics working. Old unit removed and all pipes and cabling tidied. ABS relay removed from fuse box. No brake warning lights active so no need for masking off lights. Everything being refitted (pic 1)

Old unit removed and ready for the scrapheap (pic 2)

Bike ready for a road test (pic 3)

Conclusion. Took the bike for 20 mile run. Lots of twisties and some town work. I have never been hard on brakes and can honestly feel no difference. I have arranged for a rolling road test tomorrow (and I have a note of the readout from my last MOT) so a comparison will be interested.

I am not a mechanic and no expert but with a little care and patience this is a job than can be done.

Carl · Mar 21, 2008

Nice job

Thanks for taking the time to post up the photos.

I vote this be made into a sticky. As the bikes get older servo failure may get more common

Rob Farmer · Mar 22, 2008

Pointless technology in the first place? This is the mod I'll be doing to mine if/when the servo gives up the ghost.

Glad you got it sorted and thanks for taking the time to post the excellent pictures :thumb2

delpel · Mar 22, 2008

Glad the whole job went as smoothly as mine chap. It's a bit mind boggling when you start but not rocket science as they say.

Interested in the stand from Makro's. I gather you need to remove the belly pan when lifting. How high does it go? Any photo's of where you place it would be cool.

Regards

SoFTSTuFF · Mar 22, 2008

Thanks a million Gorden :beerjug:

I saved it to my harddisk under "THINGS TO DO ON MY 1150"
Thanks a lot for the pictures and the excellent description!

Greetings Jan Willem

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