Brake Failure - possible ways to check cause

[Sharpey]

Right then. I have a brake problem, which I think is a variation on the usual story. The warning triangle is coming on mid-ride, with the brake failure warning flashing merrily away.

Cut and paste from an old post by 'Wapping' is that the very likely causes are:

(1) That the front brake lever is getting slightly caught behind the hand guard. Check that the lever can 'flick forward'. If it can't simply tilt the hand guard so that the lever can.

(2) That the rear brake switch is engaged. Adjust the rear brake pedal if it is.

Check both the above quite quickly by looking at the rear light, to see if the brake light is on.

(3) Last possibility is that the speed sensor for the ABS (behind the rear wheel) is playing up, or possibly (less common) the sensor in the front wheel. If your speedo is behaving normally, this is probably unlikely.

Due to the joy of being made redundant at Easter , I now have the time to go through all this, check the exact failure warnings, check the owner’s manual etc. etc. (I was hoping to just ride the thing as a way of forgetting the lack of work...!)

To be honest, I am not mechanically competent, don't have the tools or facilities. Yes, okay, I admit it, I am a numptie. Please be gentle with the abuse... But I've made a start in correcting that - e.g. recently did some basic wiring in of some accessories. With a strong desire to keep my money away from BMW at the moment, now would seem to be a good time to make a start on figuring out which way around a spanner goes.

I'll post back up here to let you know how it goes. If nothing works, I'd like to hear if there are any other ideas, and perhaps get some help from any mechanical geniuses in the Brum area.

David

 

[Pukmeister]

Hi David,
welcome to the growing ranks of the unemployed, you have my sympathy.

I presume your bike has Servo ABS. The servo pump sits on top of the engine beneath the fuel tank, the tank has to come off to get to it. Within the ServoABS pump unit are two fluid reservoirs which hold all the brake fluid for the front/rear circuits. The small plastic reservoirs on the handlebar/footbrake are just pilot circuits that operate the wheel circuits via the ABS pump.

The Servo ABS pump has a level sensor on each internal reservoir. As the brake pads wear with use, the pistons in the calipers move out to compensate and keep the pads in contact with the disk hence the level in the ABS pump drops. Eventually the internal reservoir level gets too low and the system senses the low level (not sure if this then triggers an ABS alarm or not but it is a possibility. I know when I did my ABS fluid change, the GS911 software told me there was a fault stored saying my fluid levels were low but I had no flashing ABS warning lamp.)

If your checks don't reveal the problem, it may be worth reading up on the ABS pump from a copy of the RepRom (repair CD) and how to replenish the fluid level OR it may be worth replacing your worn brake pads with new ones to return the brake pistons (and hence reservoir level) to a normal working level.

 

[Sharpey]

Adam - Thanks for the note. Hoping the bike will stop me doing a Yosser Hughes. (we need a smiley to say "I can do that")

Yes, its a '05 plate, with servos + ABS. In terms of looking at the brake pads etc, I will add the above in the 'list of things to look at before panicing'.

 

[Wapping]

David,

Start with the easy things first.

If the front brake / rear brake lever is catching it's easy to check, the rear brake light will (or at least should be) on. If they are catching, you may well now have residual braking only. You can tell this really easily: The brakes, when the bike is being ridden, will be a fraction of their usual efficiency, a bit like having wooden brake pads. So, do not go hooning up to a junction to find out.

If the brakes are 'normal', they may still be engaged. The hand guards can swing a bit, engaging or disengaging. Check the rear light. A good friend of mine had a very similar problem in the Alps. Descending at a fair bit of speed, up flashed the red triangle of death.....and only the residual brakes to slow his descent. The front brake lever was not the culprit. A small stone had lodged itself in the rear brake switch area, engaging the brake circuit.... Easy to fix but not a great experience on a 1:5 descent.

If the brakes are 'normal' and the rear light is off, it's more likely that there is another cause (or you brake light does not work).

From what you describe, which match my symptoms exactly, I would go next for the failure of the drive and it's gradual destruction / interference with the rear speed sensor.

Good luck.

Come back if you are stuck or (better still) when you have found the problem and fixed it.

 

[Sharpey]

Okay, after a bit of faffology, an update.

(1) The brake lights work.

(2) The front and rear levers are not catching, and appear to be working as they should.

(3) The speedo is fine too.

Other things I have thought about:

(4) Battery - I recently fitted a new Odyssey P535, with a CTEK indicator connector (thought I may as well blow some of my last month's wages with Motoworks) - so I know the battery is 100% okay

(5) Dirt and stuff making the ABS sensors play up. I am now fairly sure they are okay - I will have a more thorough go at making 100% sure over the next couple of days

(6) Break pads seem okay. However, once I look around here to gain the know-how, I may consider removing and replacing just to be 100% sure to remove another possible cause.

I am also going to have a look at understanding how the servo brake system works. Why? Well, I had a little run around Brum for a few mins, deliberately parking up for a bit before heading home, but still no working brake system. Bugger. (By the way, riding around Brum with residual breaking is 'fun') Anyway, back at the house, I decided to leave the bike for half an hour, and then switch the ignition back on. Strangely, it magically started to work again, going through the normal start-up routine.

So that I could try and understand what was happening, I had a go at making the brake system fail, but without starting the engine so I could listen to what the servos were doing. At one point, I could hear something go mental - what I think was a servo motor from above the engine - after I applied and released a brake. It happened a couple of times each with front and rear levers, and seemed to be distinct from another servo motor noise when either the front or rear levers were applied. For a while, the mental servo noise carried on and on, and then stopped, despite what I was or was not doing to the levers.

So I think it is the break servo system that is the problem, rather than the made-of-cheese final drive....

Sorry for the

David

 

[Pukmeister]

It could be the microswitch for the front handlebar brake lever. When you pull the brake lever, does the servo make a whine?

When you release the lever, does the whine then stop, or do you have to nudge the lever forward a bit to stop it?

The microswitch is set in place with a tiny allen screw from beneath, which can vibrate loose. The trick is to ensure the microswitch is working properly (May need a squirt of WD40 or contact cleaner), then set it with the allen screw so that the servo pump comes on just as the lever is pulled i.e. before you need to apply braking pressure. You will need to remove the right hand handguard to get access to the microswitch.

If either the front or rear brake microswitches are operated (perhaps due to sticking) when the bike is first turned on, the ABS self-diagnosis will throw up a fault and you will be left with residual braking which is what I think is happening to your bike.

 

[Sharpey]

The front lever is fine. Now that the brake system has decided to work for a while, when the front lever is applied, the servo whines, and as you describe, with limited movement or pressure required. When released, the lever springs back, the servo stops and break light goes of instantly.

 

[patzx12]

I would agree that the front brake light switch could be out of ajustment.
The switch is NO (normally on)
Easy to ajust unplug the connector and put a meter on the contacts.
You should have a constant signal that goes off when you pull the brake.
The switch is ajusted by loosening a little grub screw under the lever and rotating the switch.
The ajustment could be borderline causing an intermittent fault.

 

[harry]

With the Tank removed have a good look at the wiring loom down the R side of the bike. Various people have had trouble with intermittent Loom/Frame shorts.

 

[Sharpey]

Brake Problem - Beyond Me - time to call "Help...!"

Having looked at the repair DVDrom, rapidly coming to the conclusion that this is going to be beyond my competence / confidence to sort out. I know, a fairly low threshold, but I am beginning to think that I don't want to be learning bike repair sat on my driveway fiddling with the brake system...

Trip to dealer now looking likely. Ho hum. If there are any friendly GSers who are passing (Bournville), and would like to have a look, I am more than happy to be told "You're an idiot, this bit here (kick) is the problem, five minute job, easy.." before the phone call to the dealer on Tuesday.

What with other issues, beginning to think my bike is made of cheese. Usual story of rusty bits, front engine cover rubbish paint, etc... To make matters worse, while I am sat here faffing on the 'puter, my wife is pootling around having fun on her F800ST.

David.

 

[Sharpey]

I love CW Motorcycles

Just a quick update for anyone who would like to know - yes, all three of you...!

Took the bike down to CW Motorcycles, who found that the whole ABS unit had failed. CW's then went that extra distance... on the same day, the unit was replaced. After CW's negotiated with BMW on my behalf, BMW paid for the part, I paid for the labour, with a bill about a tenth of what it could have been.

Yet again, CW's have proved worth their weight in gold.

 

[ross.mcw]

All sounds similar to problems I'm having with 'my 04 GS at the moment - when I mentioned the issues to a technician at Williams BMW in Trafford, he said that it was most likely the ABS pump, which costs about £1200 odd and that I'd no chance of BMW paying for any of it.

Once the bike's back together (I decided to pull it to bits to get to know it better, give it a good clean up and see if there were any obvious issues that could be causing the problem) I'll take it in to get the error codes read and will go from there.

My last service involved some hassle getting BMW to cover the cost of fixing the final drive oil seal ('not a known issue' apparently...)

The bike's only done 10k mostly dry miles, is immaculate and has had full BMW servicing so I'll be totally pissed off with BMW if it is going to cost me that much to fix this. Love riding the bike, but I think it'll be a Honda for me next time - just can't be arsed with problems like these.

Cheers, Ross.

 

[Sharpey]

Don't abandon a bike you like just 'cos your dealer expereince is not as good as mine at CW's. I used to live in Cardiff, and got my first bike - a F650GS Dakar - from the folks who were then dealers (they closed their bike section and now I think Riders have taken on a BMW franchise).

Anyway, when the Dakar came up with a problem with the head bearing, the Cardiff lot said 'no way - BMW won't pay', despite the bike being still under the 2 year warranty. I had a look on here, seeing that others had managed to get it swapped. So I thought about ringing a couple of other dealers to get a second opinion - first bunch I spoke to were CW's - who actually offered to sort it out for me, and claim back from BMW.

It gets better. CW then saw that the paint on my front forks had started to flake - so sorted that one too.

And no surprise that when I decided to get a R1200GS, that I bought it from CW's. And despite moving to Birmingham, that's where I go for servicing.

It's a fair bargin. I pay them, they give me excellent customer service, going that extra distance when they can.

I am sure that after a search around here, you'll find the balance of reviews for some of the dealers nearer to you are above the average. Or just be nuts like me, and travel down to CW's!

 

[GSoh]

I had this problem on my 55 place 1200gs. I thought about taking it to the dealer but had a quick look over the brakes myself and thought the rear calliper looked like it could do with a service. The pad retention pin and shim were rusty as hell after riding through the winter so I replaced these, cleaned the pistons and all is fine now.

 

[Will B]

With the Tank removed have a good look at the wiring loom down the R side of the bike. Various people have had trouble with intermittent Loom/Frame shorts.

my 04 1200 had three visits to dealer before damage the wiring loom was found to be the fault. i believe the damage to the loom was near the fuel tank - could be a good place to start looking.

 

[ross.mcw]

All sounds similar to problems I'm having with 'my 04 GS at the moment - when I mentioned the issues to a technician at Williams BMW in Trafford, he said that it was most likely the ABS pump, which costs about £1200 odd and that I'd no chance of BMW paying for any of it.

Once the bike's back together (I decided to pull it to bits to get to know it better, give it a good clean up and see if there were any obvious issues that could be causing the problem) I'll take it in to get the error codes read and will go from there.

My last service involved some hassle getting BMW to cover the cost of fixing the final drive oil seal ('not a known issue' apparently...)

The bike's only done 10k mostly dry miles, is immaculate and has had full BMW servicing so I'll be totally pissed off with BMW if it is going to cost me that much to fix this. Love riding the bike, but I think it'll be a Honda for me next time - just can't be arsed with problems like these.

Cheers, Ross.

Finally got round to taking the bike into BMW and no surprise, it was the ABS pump/servo unit that's failed/failing. £1300 plus abotu £200 fitting. Thankfully after some pleading with the service lady and a couple of calls to BMW, they've agreed to cover the entire cost.

So, still shocked that stuff like this breaks so early on such an expensive bike, but very happy that BMW have stumped up on a 5 year old bike (it is immaculate though).

Anyhow, based on that, I'm probably going to buy a new GSA and will sell my 2004 'GS.

Cheers, Ross.

 

[Sharpey]

Ross,

Good to hear you got it sorted okay.

I know where you are coming from on the Adv... ...somehow I managed to land a job within 3 months of finishing my last one - and the deal with my Mrs was that, if I managed that, I could part-ex the old one and get an Adv...

...which is now sat outside the house

David

 

[RogerJ]

Glad things are working out for you all. My 07 ADV had a fault "low voltage arriving at the ABS modulator." Turned out to be a fault in the wiring loom AND the ABS modulator was toast. Both replaced as was clearly within warranty.
So...should you get the ABS warning light a useful early step is a scan. If you or a mate has a GS-911 hook it up and see what it says. Will usually lead you to what you need to check out to resolve the problem. It is not that unusual to have wiring loom and/or frame abrasion issues around the tank area leading to faults and failures.

 

[gazabmw]

'Brake Failure' warning light

I have an 06 1200GS, low mileage bought second hand this year. Coming DOWN a Pyrenees mountain last month, and the 'Brake Failure' warning light came on, together with the red warning light. Scary !
Not the sort of thing you want to see descending ! Checked the brakes and there was no problem, servo worked and brakes fine. I was not using the brakes heavily as engine braking is so good anyway, but it was hot 25-30 degrees.
Stopped bike, engine off. Waited a few mins, then restarted. No problem.
It did come on again for a short time on the valley floor but after stopping again no problem. Never happened again on trip nor back in blighty.
Phoned Ocean BMW when I returned, they thought that maybe ABS sensor got a bit hot, and said if it occurs again ( it hasn't) they will look at it.

 

[h0wz3r]

Those of you who had your bikes sorted by BMW, am I assuming you had warranty on them?

Just bought a 54 plate R1200GS so obviously it's out of warranty but wondered if I ever came across a problem like this, is it possible that BMW would sort it out? As it's a 2004/2005 bike I'm sure it's got servo-assisted ABS brakes. Certainly it's got ABS anyway.