Rear brake servo failure

[Motocod]

I can't tell you the age of the battery, but I can tell you it's in good condition, as it's permanently plugged in to an Optimiser when the bike is parked up.

My old battery was permanently plugged into an optimate right up to when it went tits up.New battery fitted everything fine.

Doesn't make much sense does it?! How much would a new battery set me back?

Nik

[DaveH]

Try Motorworks - OEM spec batteries are good and right money - £69

[metropolis2k]

I've only just seen this thread. Sorry to read about your ABS issues! (We met at Brands Hatch with the almost identical bikes).

Have you been able to get a fault code from the flashing lights? I've only ever pulled a fault code with a home-made LED for a non-servo bike but I believe with the servo models the rate at which the lights flash should tell you what the error is.

This is my bible when it comes to BMW ABS faults: http://www.largiader.com/abs/absfault.html

[Motocod]

Thanks for the link. It would appear I have the iABS, and my warning light is flashing at 4hz. Hard to know what to do next. I don't have the time to fix it, it's hard to get the bike to a dealer (it's presently on the Isle of Wight), and all the while I just want a bike to ride. Pretty close to just selling as-is and accepting a loss due to the fault...

Realistically I'm probably going to have to try and get it to Bahnstormers (or whatever they're called) and have the fault properly diagnosed, and go from there. Unfortunately my new job means I'm not at home enough to spend time on it, and I'm not completely convinced that a new battery will sort it - reading the link above seems to suggest to me that the battery thing is for the earlier ABS types, unless I'm missing something.

Pretty stuck here, and really rather frustrated with an immobile and unusable bike. Any ideas or suggestions (or offers to purchase!!) would be welcomed...

Nik

[Bruno]

I've recently had the exact same symptoms on my 2002 iABS bike.
No rear power assistance, but the front still as normal.
Fast flash warning light.
The first time I had the fault I switched off the ignition, restarted and normal service was resumed. But the next day it happened again, and again until now it begins to reset itself but then presents the fault before the engine is actually fired up.
I've researched and come up with several possible solutions. In the end I asked a friend who is a local independant BMW expert.

He said that it was a fairly common problem. His opinion is that a new battery wouldn't help. A battery fault would affect front and rear brakes. (I can confirm that. In the past my alternator belt failed, leaving me with a flat battery and no power assistance at all, on the moterway)

His diagnosis was that there was indeed a problem with the pump. The cheap solution was an ABSectomy.

1) Drain the brake fluid from the servo unit. That way you don't get fluid all over.
2) Replumb the front brake.
Theres a part from Motorworks BRA50965A £12.90. Its a link pipe that fits in the front brake circuit. It bypasses the pump, so that the hose from the master cylinder is directly connected to the feed to the calipers. It goes on the right hand side of the headstock just in front of the bodywork.
3) Replumb the rear brake.
Disconnect the hose at the pedel end and connect it directly to the master cylinder. Looking at mine, I'm not sure theres enough slack in the hose, but I do have a slightly longer hose from another project if needed.
4) Remove the ABS relay; stops the warning light flashing.
5) Leave the wiring plugged into the ABS unit, so that the speedo still receives its signal from the rear wheel sensor.

The hard brake pipes can be disconnected from the servo unit, and removed from the bike. I was given a set of transit plugs used to keep dust out of replacement units. I'll use them to ensure no stray drops of b/f don't leak out of the servo. You could cut and crimp over the ends of the pipes.
I suppose you could leave the pipework in place in the hope that the fix is reversable if a new or repaired servo turned up at a good price in the future.
I've heard it suggested that the electronic connections can be spliced and the pump unit completely removed. I've also heard that the electrical part of the pump can be unbolted,and plugged back into the loom. This would maintain wiring integrity, whilst allowing removal of the pump metalwork.

My choice is to fit a front link pipe (£13). Reroute the rear hose (possibly free, or new line, £25-£30 ish). Pull the relay, remove the hard pipework, leave the pump in place.
Looking at Motorworks' picture of the link pipe, you could probably have one made up by a local motor factor, or DIY if you have a pipe flaring tool.

I'm in the process of doing this at the moment. I'll let you know how I get on. Hopefully the brakes will retain good braking effect. I've heard the discussions regarding insurance implications.

Mark

[big rob]

I've recently had the exact same symptoms on my 2002 iABS bike.
No rear power assistance, but the front still as normal.
Fast flash warning light.
The first time I had the fault I switched off the ignition, restarted and normal service was resumed. But the next day it happened again, and again until now it begins to reset itself but then presents the fault before the engine is actually fired up.
I've researched and come up with several possible solutions. In the end I asked a friend who is a local independant BMW expert.

He said that it was a fairly common problem. His opinion is that a new battery wouldn't help. A battery fault would affect front and rear brakes. (I can confirm that. In the past my alternator belt failed, leaving me with a flat battery and no power assistance at all, on the moterway)

His diagnosis was that there was indeed a problem with the pump. The cheap solution was an ABSectomy.


I'm in the process of doing this at the moment. I'll let you know how I get on. Hopefully the brakes will retain good braking effect. I've heard the discussions regarding insurance implications.

Mark

Our 11S was done over 3-years ago, haven't noticed too much difference when applying the brakes, should also mention the bike has sailed through 3 MOT's since its' ABSectomy.

[metropolis2k]

Thanks for the link. It would appear I have the iABS, and my warning light is flashing at 4hz. Hard to know what to do next.

Ah yes, that is a pain because the error messages aren't as useful on iABS as they are on ABS2.

Have you tried to see if Bahnstormers will collect the bike? Personally I'd try to get a quote for the work (either replace a faulty part or remove it entirely?) and compare it to doing an ABS-ectomy yourself or selling it as it is.

[Motocod]

I've recently had the exact same symptoms on my 2002 iABS bike.
No rear power assistance, but the front still as normal.
Fast flash warning light.
The first time I had the fault I switched off the ignition, restarted and normal service was resumed. But the next day it happened again, and again until now it begins to reset itself but then presents the fault before the engine is actually fired up.
I've researched and come up with several possible solutions. In the end I asked a friend who is a local independant BMW expert.

He said that it was a fairly common problem. His opinion is that a new battery wouldn't help. A battery fault would affect front and rear brakes. (I can confirm that. In the past my alternator belt failed, leaving me with a flat battery and no power assistance at all, on the moterway)

His diagnosis was that there was indeed a problem with the pump. The cheap solution was an ABSectomy.

1) Drain the brake fluid from the servo unit. That way you don't get fluid all over.
2) Replumb the front brake.
Theres a part from Motorworks BRA50965A £12.90. Its a link pipe that fits in the front brake circuit. It bypasses the pump, so that the hose from the master cylinder is directly connected to the feed to the calipers. It goes on the right hand side of the headstock just in front of the bodywork.
3) Replumb the rear brake.
Disconnect the hose at the pedel end and connect it directly to the master cylinder. Looking at mine, I'm not sure theres enough slack in the hose, but I do have a slightly longer hose from another project if needed.
4) Remove the ABS relay; stops the warning light flashing.
5) Leave the wiring plugged into the ABS unit, so that the speedo still receives its signal from the rear wheel sensor.

The hard brake pipes can be disconnected from the servo unit, and removed from the bike. I was given a set of transit plugs used to keep dust out of replacement units. I'll use them to ensure no stray drops of b/f don't leak out of the servo. You could cut and crimp over the ends of the pipes.
I suppose you could leave the pipework in place in the hope that the fix is reversable if a new or repaired servo turned up at a good price in the future.
I've heard it suggested that the electronic connections can be spliced and the pump unit completely removed. I've also heard that the electrical part of the pump can be unbolted,and plugged back into the loom. This would maintain wiring integrity, whilst allowing removal of the pump metalwork.

My choice is to fit a front link pipe (£13). Reroute the rear hose (possibly free, or new line, £25-£30 ish). Pull the relay, remove the hard pipework, leave the pump in place.
Looking at Motorworks' picture of the link pipe, you could probably have one made up by a local motor factor, or DIY if you have a pipe flaring tool.

I'm in the process of doing this at the moment. I'll let you know how I get on. Hopefully the brakes will retain good braking effect. I've heard the discussions regarding insurance implications.

Mark

Thanks for your post Mark, I'm glad to hear of another person having the same issue. As it happens I've been sitting here this morning pondering the bike and was thinking exactly what you've done - to bypass the ABS. Seems a shame, but it's a cheap fix to get my mobile again.

It may be that the bike ends up going to a dealer to have it done, as I just don't really have the time due to work, but this seems like by far the best option for me.

Thank you so much for posting, it's really appreciated.

Just thinking about it, I'd ideally want to remove the servo and ABS entirely, and save a chunk of weight. I'll need to investigate whether that's possible.

The good news is this is a glimmer of hope for me getting riding again, so I'm delighted. Thanks again Mark!

Nik

[Motocod]

Thanks for the link. It would appear I have the iABS, and my warning light is flashing at 4hz. Hard to know what to do next.

Ah yes, that is a pain because the error messages aren't as useful on iABS as they are on ABS2.

Have you tried to see if Bahnstormers will collect the bike? Personally I'd try to get a quote for the work (either replace a faulty part or remove it entirely?) and compare it to doing an ABS-ectomy yourself or selling it as it is.

Bahnstormers can collect, so I will probably look at doing that, and getting them to bypass the ABS for me, and do an MoT and service at the same time.

Nik

[Motocod]

Just booked the bike in to be collected by Bahnstormers. The earliest they can look at it is the end of the month, which I guess gives me a bit of time to decide what to do with it. They've said they wouldn't get involved in doing an ABSectomy though, so I might have a re-think, as I could potentially end up with the bike stuck there with no MoT and an expensive ABS fault I'm not prepared to pay for. Time to ponder...

Nik

[mole2000]

Re reroute of ABS to non ABS, why pay main dealers prices, my local independant could collect and repair at a fair price I'm sure. Know he's done same job b4!
Don't want to get into trouble so won't post his contact details, but happy to pass them on.
He's not too far from Bahnstormers either!!

[Motocod]

Re reroute of ABS to non ABS, why pay main dealers prices, my local independant could collect and repair at a fair price I'm sure. Know he's done same job b4!
Don't want to get into trouble so won't post his contact details, but happy to pass them on.
He's not too far from Bahnstormers either!!

Spoke to Garry last night and we've tentatively arranged for him to collect the bike on Saturday. So I'm finally on the way to having a functional bike again! He's got some horror stories about the abs system, that's for sure!

Nik

[markwin]

Had the same issue and after a lot of checking went the route of ABS removal.Have a good and thorough look on this site as there is all the info you need.After reading about iabs and NOT liking the servo action of the brakes I would have prob disconnected anyway as I can now trust the brakes-why BMW thought putting a servo onto the bike was a good idea is unfathomable.went for full removal of pump etc and you can really feel the loss of this weight high above the CoG.dont give up ,its a bit of a pain but if you otherwise like the bike take a deep breath and do it or get it done by someone you trust.As far as insurance implications go the GOLDEN RULE is inform your insurance provider , I told them that the system has been removed and they had no problem with that and the premium did not alter-at each renewal ensure they have a note recorded-don't trust them as mistakes can be made and you must be absolutely sure they cannot wriggle out of a claim due to non disclosure.Good luck you will soon be riding again and you will learn a lot more about your bike even if you didn't want to....

[andy griff]

Good stuff Nik, keep at it - it will come right

[Motocod]

Thanks Andy! It's good to know it's on the way to getting sorted, finally. Will be great to ride it again - I've barely done 200 miles this year, which is pitiful!

Nik