2018 R1200GS spongy rear brake-rear brake uneffective

8883 Views 15 Replies 11 Participants Last post by Scurvy, 10 d ago

Donbus

Discussion Starter · Dec 5, 2019

I realize there have been a couple posts on this topic, but I thought this new info warranted a new post. After experiencing this issue "spongy rear brake" on my 2018 R1200GSW I mentioned it to my nearby dealer in Denver and to my surprise they said they would replace the rear master cylinder under warranty just based on my description. When trying to apply the rear brake the pedal would travel more than 2" before any braking would occur and the braking power was very weak. Front brake was not affected. Once they replaced the part and bled brakes I was astonished how well they now worked. The mechanic said BMW had done some redesign on the master cylinder to remedy the air leak issue. I would encourage anyone with this issue to contact their dealer. I'm a little surprised this has not been a recall item as brakes are a pretty important safety item. This may apply to other year WC GS's.

1 - 16 of 16 Posts

Maturerider

· #2 · Dec 5, 2019

I had this issue on my 2014 R1200GS. My dealer replaced the master cylinder. Interestingly I recently had the same problem with my 2019 R1250GS but this time they just bled the brakes. Works fine at the moment but suspect if it happens again they will replace the master cylinder.

Remember the brakes are Brembo (fortunately the fronts are now Haynes). They're Italian. Like Fiat and Ducrapi..........

enzo5000

· #3 · Dec 5, 2019 (Edited)

If you own or have access to a GS-911 diagnostic tool. Follow this well done video. It fixed my spongy rear brake on my 2017 GSA and took less than an hour to complete.

Total parts was about $70.00 and now I can do the bleed and flush easily if the rear brakes become spongy again.

https://www.amazon.com/GS-911-OBD-I...ocphy=9031638&hvtargid=pla-528892039806&psc=1

Rider2

· #4 · Dec 7, 2019

Had the same thing on my 2016 GSA - no rear brake at all. Dealer fixed it with a flush/bleed, it happened to coincide with the three-year service. It was WAY out of warranty, so I'm sure I rode out with the same master cylinder I arrived with. It's one of those things they won't just do as a goodwill item and not tell you about. Parts fiche from Bob's BMW shows it as $217 and change (plus labor, of course).

Unrelated, I just noticed that both places I check parts prices (Max BMW and Bob's BMW) haven't updated their parts fiches for quite a while - for the R1200 GSA there's nothing newer than MY 2014 - so no R1250 parts. Has the mothership decided to restrict current information to only professional parts-looker-uppers, i.e. the ones employed in authorized service facilities?

ParkRider

· #5 · Sep 27, 2020

Donbus said:
I realize there have been a couple posts on this topic, but I thought this new info warranted a new post. After experiencing this issue "spongy rear brake" on my 2018 R1200GSW I mentioned it to my nearby dealer in Denver and to my surprise they said they would replace the rear master cylinder under warranty just based on my description. When trying to apply the rear brake the pedal would travel more than 2" before any braking would occur and the braking power was very weak. Front brake was not affected. Once they replaced the part and bled brakes I was astonished how well they now worked. The mechanic said BMW had done some redesign on the master cylinder to remedy the air leak issue. I would encourage anyone with this issue to contact their dealer. I'm a little surprised this has not been a recall item as brakes are a pretty important safety item. This may apply to other year WC GS's.

Just curious has this solved your issue, I’ve been having the same issue with the rear brake getting spongy after 8000 kilometres on my 2018 R1200GS. Thanks

Mark_M

· #6 · Sep 27, 2020

I had the same thing happen on my 2019 R1250 GSA. The forum pointed me to this link....

advrider.com

bmw r1200gs lc rear brake failures

i searched and failed to find any posting regarding rear brake failures on bmw r1200gs lc and so, i'm posting this to share my experience and hear from...

advrider.com

virkdoc

· #7 · Sep 27, 2020

ParkRider said:
Just curious has this solved your issue, I’ve been having the same issue with the rear brake getting spongy after 8000 kilometres on my 2018 R1200GS. Thanks

This is a problem a lot of us have and is covered extensivley on advrider.....I have a 2018 GSA and the same spongy rear brake.....they bled it three times, changed a few seals but it would come back. I finally showed them all the posts.....they changed the rear MC and bingo brake works amazingly well till now....been a few thousand kilometres now

ParkRider

· #8 · Sep 27, 2020

Mark_M said:
I had the same thing happen on my 2019 R1250 GSA. The forum pointed me to this link....

bmw r1200gs lc rear brake failures

i searched and failed to find any posting regarding rear brake failures on bmw r1200gs lc and so, i'm posting this to share my experience and hear from...

advrider.com

Thanks Mark, going to see if they can change my MC under warranty

Mauricio

· #9 · May 2, 2021

virkdoc said:
This is a problem a lot of us have and is covered extensivley on advrider.....I have a 2018 GSA and the same spongy rear brake.....they bled it three times, changed a few seals but it would come back. I finally showed them all the posts.....they changed the rear MC and bingo brake works amazingly well till now....been a few thousand kilometres now

Hi. Can you tell us if the problem finally resolved? Or after additional miles it returned again. Thanks.

virkdoc

· #10 · May 2, 2021

Mauricio said:
Hi. Can you tell us if the problem finally resolved? Or after additional miles it returned again. Thanks.

Its back again.....so it wasnt the master cylinder i guess. Came back after 15,000kms though

Donbus

Discussion Starter · #11 · Dec 7, 2021

I initiated this post and now 2 years later the problem has reappeared. talked to local BMW dealer and they said they were willing to charge me $139 per hour labor rate to investigate the problem and then maybe it would be covered again even though out of warranty. I am totally amazed this has not been properly re-engineered and a recall issued regarding something as critical to safety as brakes on a motorcycle.

Krons

· #12 · Dec 8, 2021

Donbus said:
I initiated this post and now 2 years later the problem has reappeared. talked to local BMW dealer and they said they were willing to charge me $139 per hour labor rate to investigate the problem and then maybe it would be covered again even though out of warranty. I am totally amazed this has not been properly re-engineered and a recall issued regarding something as critical to safety as brakes on a motorcycle.

I think it is fair to ask what their "investigation" would be. If they charge $150 for a brake bleed you can do that yourself.

Donbus

Discussion Starter · #13 · Dec 8, 2021

ParkRider said:
Just curious has this solved your issue, I’ve been having the same issue with the rear brake getting spongy after 8000 kilometres on my 2018 R1200GS. Thanks

It worked ok for about 1 1/2 years, now the problem is back.

Scurvy

· #14 · 11 d ago

enzo5000 said:
If you own or have access to a GS-911 diagnostic tool. Follow this well done video. It fixed my spongy rear brake on my 2017 GSA and took less than an hour to complete.

Total parts was about $70.00 and now I can do the bleed and flush easily if the rear brakes become spongy again.

https://www.amazon.com/GS-911-OBD-I...ocphy=9031638&hvtargid=pla-528892039806&psc=1

I followed the video and used my GS-911, and while the rear brake will actually stop the bike now if I m going slowly enough, it only does so when I jam the pedal all the way down. Also, the first 50% of its travel does ZERO braking. Could this be a pedal adjustment issue?

Along the way of my wrenching, I followed the old-fashioned wisdom of bleeding the caliper furthest from the control module (ABS) first (the rear) and then did the fronts. It worked well, and what I discovered was that the GS-911 bleed routine released a lot air to the rear, and then when I bled the fronts, there was zero air, presumably because the rear bleed let it all out.

The take-away is the pre-GS-911 bleed released some air from all the calipers, and then post-GS-911, we can save time by clearing the air from the single rear caliper rather than fussing with all 3 calipers.

TSConver

· #15 · 11 d ago

The front and rear calipers are not connected physically to each other. Bleeding the rear has no impact on the front and vice a versa.

Scurvy

· #16 · 10 d ago

TSConver said:
The front and rear calipers are not connected physically to each other. Bleeding the rear has no impact on the front and vice a versa.

Yes, but what is interesting is that prior to the wrenching, the rear was non-existent and the front had fade, yet I only extracted micro-bubbles from the front lines when I first bled them. Then, after the GS-911 bleed routine, there was significant air released by the rear bleed and zero air from either front caliper.

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