Rear brake pedal right down "Excessive travel"

[GrinningGSer]

As per title , my rear brake pedal goes right down , with very minimal, usually no braking effect. Its happened four times now (One was an MOT failure "Excessive travel ")
(I suspect rear master cylinder failure, but hey, I'm an amateur spanner)
1200GSA. No fluid loss whatsoever ! Always fixed by bleeding both brakes and ABS unit (GS911)
1000 miles later, excessive travel issue starts again
So the bike goes into dealer, who understandably wishes to do their own documented bleed .
HOWEVER , I'm today told that they've "done a software update to give me more pressure "
Is there any way, whatsoever, that software can fix my recurring problem ?
They know that I'm stupid.
Edit : many threads on this similar issue

 

[Bigcats]

Funnily enough mine has just gone in for its MOT and was picked up for having 'excessive travel' on the rear brake (which I must admit was soft but to me bikes are known to have poor back brakes)

£27 later after they bled it and all is good so time will tell

But potentially it could be because its linked to the front brake that is why it goes over time (as the rear pad wears as well)

 

[GB.]

For some reason the LC rear brake seems to need regular bleeding. I also purge it with the gs911 tool, that makes the pedal much firmer.

 

[TIJ650]

This is very common with the linked brakes - especially (like me) if you seldom press rear pedal. It’s easily fixed with a rear brake bleed. I’ve been told by Motorrad to press rear pedal more often, but I opted for the Stahlbus speed bleeder and GS911 for the ABS bleed.
It’s a common fault that the Nazi’s will never admit to


Sent from my iPhone using Tapatalk

 

[Victor c]

There is a technical bulletin for this https://www.tsbsearch.com/BMW-Motorcycle/SIB-34-01-21

 

[GrinningGSer]

Intertesting Victor C, not that I understand much of that technical bulletin : It looks as though there are indeed software pressure set points

 

[Victor c]

Intertesting Victor C, not that I understand much of that technical bulletin : It looks as though there are indeed software pressure set points

My 2016 GS suffered with it, but my 2 subsequent GSAs have not.

 

[TIJ650]

There is a technical bulletin for this https://www.tsbsearch.com/BMW-Motorcycle/SIB-34-01-21

It would seem BMW are aware of this glitch and should repair inside or out the warranty period……….or even as a recall.
I mostly only use the front brake lever anyway (since they’re linked) but have to perform the abs/ rear brake bleed before MOT every 2nd year. Maybe worth taking the bike to Motorrad for MOT and showing them bulletin if any hassle with passing


Sent from my iPhone using Tapatalk

 

[GrinningGSer]

Well, 100 miles since I posted this problem (1200 WC GSA 2014) and after receiving a dealer brake bleed (against my wishes, but understand their need), and after having some mysterious sort of software pressure alteration ...... my rear pedal is now down to the bottom stop again. Bike going back in January . Can anyone explain the mechanics of linked brakes i.e. where decisions are made and how ?
p.s. Dealer commented "We don't see many of these bikes"

 

[TIJ650]

Well, 100 miles since I posted this problem (1200 WC GSA 2014) and after receiving a dealer brake bleed (against my wishes, but understand their need), and after having some mysterious sort of software pressure alteration ...... my rear pedal is now down to the bottom stop again. Bike going back in January . Can anyone explain the mechanics of linked brakes i.e. where decisions are made and how ?
p.s. Dealer commented "We don't see many of these bikes"

I don’t think there’s a permanent cure if your bike has the affliction, just a work around. Like I said, speed bleeder from Santa might be the ticket
PS. Regarding comments - they always say this!


Sent from my iPhone using Tapatalk

 

[Digger john]

One trick i. Was told and it works is secure a heavy weight on the rear brake pedal ,and leave on fo 24 hours it has to be heavy enough to keep the brake depresed

 

[GrinningGSer]

One trick i. Was told and it works is secure a heavy weight on the rear brake pedal ,and leave on fo 24 hours it has to be heavy enough to keep the brake depresed

Yes indeed and I was originally advised to do that myself , “after three of four bleeds “ by the dealer , and I did with superb hard results , but then went downhill again a week later . After which , dealer had a go and now 100 miles later that job has failed .
(It doesn’t need much weight overnight to achieve a good pedal )

 

[Fullchat]

Yes indeed and I was originally advised to do that myself , “after three of four bleeds “ by the dealer , and I did with superb hard results , but then went downhill again a week later . After which , dealer had a go and now 100 miles later that job has failed .
(It doesn’t need much weight overnight to achieve a good pedal )

I did this and then bled. A few bubbles came out of the bleed nipple. A firmer pedal was restored for a while.

 

[GrinningGSer]

Sorry for delay but my excessive travel brake pedal is hopefully now fixed ;
Summary ;
Multiple bleeds only temporary fix
Dealer needed to do their own bleed ; failed yet again after only 100 miles
Dealer not sure what to do so needed advice from BMW Technical support who advised ‘Replace ABS pump’
£1,400 ABS pump + Labour , involving tank removal , re fill and bleed + VAT
Must have been ‘north of ‘ £2k . All covered by my ongoing BMW extended warranty .
My 1200GSA is now known as ‘Trigger’s Broom’, as a result of all the multitude of very expensive parts fitted ( under extended warranty) in the last 12 months and these repairs costs have equalled all of the ‘peace of mind’ premiums that I’ve paid in the last seven years.

 

[asifmo]

I had this same problem with my 2013 lc, within 10 miles of bleeding I would lose rear brakes, tried and replaced the bits MC, rear calliper, LV fluid and then eventually replaced the ABS pump with the latest part number which looks to have done the job. Due in to BMW in a couple of weeks to code the ABS pump to the bike but brakes are all working fine over the last 500 miles or so.

Interestingly, I used the Comma esc LV fluid from Halfords and it added to my woes as it would leak past the bleed nipple including on the front. I replaced with standard dot4 and no more leaks.

 

[MartinK]

Timely reading?
Happens on a mate's 2015 GS, but my own (owned from new, 6 years old and 33000 miles) has just exhibited the same thing for the first time in it's life....
It's on for it's "B" service on Tuesday, and I'll be raising the issue with the mechanic - I trust this mechanic so I'll tell you what he says...
(Mechanic is ex head technician at Motorrad Central, he definitely knows his bmw bikes!!!)

 

[TIJ650]

Timely reading?
Happens on a mate's 2015 GS, but my own (owned from new, 6 years old and 33000 miles) has just exhibited the same thing for the first time in it's life....
It's on for it's "B" service on Tuesday, and I'll be raising the issue with the mechanic - I trust this mechanic so I'll tell you what he says...
(Mechanic is ex head technician at Motorrad Central, he definitely knows his bmw bikes!!!)

I think there’s varying degrees of this. Mine developed this when it was 3 years old. Of course Motorrad said I was the only one that’d complained about it. I might be wrong, but ever since I started using the back pedal as opposed to just the linked front, it’s all but gone.
I usually bleed both brakes when I do the ABS bleed with the GS-911 anyway.
PS. @MartinK don’t suppose you want to share the wealth with your mechanic’s name?? I need my valve shims done soon

 

[GrinningGSer]

As OP on this thread, I can report that my rear pedal is still good, 1.5 years later.
Everyone should try bleeding first , as I was correctly advised.
That failed , I guess most would replace the rear brake master pump , but that’s not what BMW advised.
The ABS pump replacement , which has fixed mine, is not a cheap job .

 

[MartinK]

PS. @MartinK don’t suppose you want to share the wealth with your mechanic’s name?? I need my valve shims done soon

Hey bud, it's Callum. His company is Central Customs: https://www.centralcustoms.co.uk/
"Now after over a decade working in the trade, most notably as a senior technician at BMW, I have the opportunity to open my own workshop."

It's really interesting talking to him. He seems scathing about how the Motorrad franchises work. For instance, my bike has had 3 left-hand throttle bodies. Bowker (when I lived in Cumbria) always refused to look further (which hacked me off as an ex-engineer I would have wanted to do a root cause diagnosis/analysis to see WHY they were failing?), and Bowker just swapped the throttle body without question, because that is what the BMW warranty claim said should happen (even tho I protested, Bowker just said "we only do what BMW tell us to do!). Because of the throttle body issues, my bike went into "limp mode" in Italy, Transylvania, and Portugal - very frustrating! The Bowker Motorrad mechanic was given the part, and allocated 1.5 hours to do the repair - this also hacked-off Callum, because he knew he could offer a better service to the customer... I'll be paying him for a whole day to do my service (I have asked him to look at a couple of other things too) - but if this was a Motorrad workshop the basic servicing would probably be done by the tea boy I've also agreed with Callum (spoke to him yesterday) that I will drop the bike on Monday night so he can do the valve clearances first thing Tuesday whilst the engine is cold.
He always has the bike on the ramp in the workshop when I go to collect it, and he talks me around what he has seen on my bike, and shows me any parts he has replaced, and explains the reasons for doing so.

I'm a Blood Biker, and Blood Bikes Scotland now take their out-of-warranty BMW's to Callum as well

 

[Stevie4scoops]

My 2019 1250 GS lost it's rear brake pressure completely on a trip to Portugal.

I'd changed the fluid not long before we went because I'd only just bought the bike but bled it when I got home and thankfully it's been OK ever since.

I've had a similar issue on both a KTM 390 and 690 Dukes but the cause was me adjusting the height of the rear brake pedal. I didn't believe the pedal position I'd change it to interfered with the master cylinder but it must have done because after changing them there was no problem.