Rear Brake Fluid - 2014 F800GT

105258 · Aug 6, 2014

My wife has a 2014 F800GT with 16,000kms on the bike. After about 10,000kms I noticed the rear brake fluid was very dark, but not the front. At the Rally in St. Paul I noticed that all the GT's have the same problem. I flushed the fluifd this morning and it was extremely dark, like coffee. I talked to the dealer and he said not to worry about this, but it seems to me that there is some contamination. Has anyone else noticed this and have a solution.?

RadioFlyer · Aug 7, 2014

Relax

105258 said:
My wife has a 2014 F800GT with 16,000kms on the bike. After about 10,000kms I noticed the rear brake fluid was very dark, but not the front. At the Rally in St. Paul I noticed that all the GT's have the same problem. I flushed the fluifd this morning and it was extremely dark, like coffee. I talked to the dealer and he said not to worry about this, but it seems to me that there is some contamination. Has anyone else noticed this and have a solution.?

Relax, all the F650/700/800 bikes do this. It's colour from the tube that connects the reservoir to the master cylinder. It's harmless. Goes away after a flush or two.

mike

pauls1150 · Aug 7, 2014

Not familiar with the F twins, but I have to ask -

The dye (or some other coating?) from inside the hose is coming off and changing the fluid's color???

Sure sounds like contamination to me... potential for a recall...?

toooldtocare · Aug 7, 2014

My first F bike was a F800S that I bough new in 2007, my last is a 2014 F700GS also bought new. Both turned black within a few miles, others that I have seen have too. Never met anyone that this hasn't happened to. Never met anyone that had any mechanical issues with it either. The color does not warrant a recall, mechanical failures do.

weschmann · Aug 7, 2014

toooldtocare said:
My first F bike was a F800S that I bough new in 2007, my last is a 2014 F700GS also bought new. Both turned black within a few miles, others that I have seen have too. Never met anyone that this hasn't happened to. Never met anyone that had any mechanical issues with it either. The color does not warrant a recall, mechanical failures do.

I've got 14000 miles on the original brake fluid since I picked up my 700 GS in January. Just completed the 12000 mile service 2000 miles late due to being on the road when crossing the 12000 mile mark, and my dealer said it was nothing to be concerned about. The valves, on the other hand, (all eight) we're seriously on the loose side, out of spec. First time I've ever experienced any valves needing adjustment at the first valve check, and all of the out of spec. At least they were all loose! My gas mileage has jumped 8 mpg average according to the on board computer....soooo, the money was well spent on the first valve check. Bike runs like a top now, with a perceived increase in power, but that could just be a biased perspective as it always seems that a bike runs better after a service appointment. I guess it should though :heart

98lee · Aug 7, 2014

Aren't the brake lines on the new bikes teflon lined stainless lines?? If so, there should be nothing on the inside of the line that could make the fluid turn color.

Old style rubber lines-yes, but new style teflon/stainless lines-no.

:dance

toooldtocare · Aug 7, 2014

Lee, yes,,,,and no. The line from the master cylinder to caliper is SS, but the feed from the fluid reservoir to the master cylinder is black "rubber." I assume this feed line is what is coloring the fluid. I guess this is why the front does not discolor.

Wayne

98lee · Aug 7, 2014

toooldtocare said:
Lee, yes,,,,and no. The line from the master cylinder to caliper is SS, but the feed from the fluid reservoir to the master cylinder is black "rubber." I assume this feed line is what is coloring the fluid. I guess this is why the front does not discolor.

Wayne

Oh yeah, forgot about that line. Makes sense.

:dance

pauls1150 · Aug 8, 2014

Sorry, guys, I'm just not drinking the faktory kool-aid here. Still sounds like contamination to me. While I agree that "color" may not be a valid reason for concern, as far as I'm concerned, ANYTHING that is in the line that isn't brake fluid does not belong there.

Being concerned about color may be lame and useless, considering the rainbow of fluids available, but being concerned about what is causing the discoloration is not.
It may be a coating from the inside of the el-cheapo rubber hose (black?), rust (brown?), or electrolysis of dissimilar metals reacting to each other (threaded or crimped fittings).

Nice that it seems to flush out, but still...

pauls1150 · Aug 8, 2014

Another Possibility

The twins have had recalls due to the rear axle...

Possibly the misalignment here is causing over-heating of the brake pads & fluid, and THAT is why the fluid turns dark? Additionally, as the pads wear, less heat is generated, so the replacement fluid remains clear.

bikerfish1100 · Aug 11, 2014

recall was on front axle, not rear. (at least, that's what my '09 GS had done)

not an alignment issue, but a strength issue.

toooldtocare · Aug 11, 2014

I looked at my bike again. There is approximately two feet of tubing from the rear caliper to the ABS module, the ABS module contains fluid, more than another foot of tubing to the master cylinder, and finally a foot of black "rubber/plastic" tubing to the reservoir. I find it hard to believe that fluid from the "overheated" caliper would migrate all that distance to the reservoir, especially in only a few miles.

The fluid does not travel back and forth in the system. When the brake pedal is pushed, only a very small amount of fluid actually travels through the system, how much, I don't know. But, I do know that when I bleed my brakes, and I push the pedal FULLY from top to bottom, the fluid in the bleed tube only moves a couple of inches, not the feet that would be needed.

Brake fluid contains solvents, it will dissolve paint. I am sure it can leach some color out of the rubber components in the brake system. This issue has been going on for years, even on the Ducati forum they mention it. I've owned Ducati's too, and saw the same thing on both my Ducati Monsters (750 and 900).

pauls1150 · Aug 11, 2014

Rear Wheel - http://forums.bmwmoa.org/showthread.php?70931-Rear-wheel-bearing-failure

Like I said in my initial post, I'm not familiar with the F twins. But OK, if there is that much separation between the affected parts, then I have to agree that overheating is not changing the fluid's color. Thank you for explaining that.

105258 · Aug 16, 2014

Re- Colored Brake Fluid

bmwroadsterca said:
Relax, all the F650/700/800 bikes do this. It's colour from the tube that connects the reservoir to the master cylinder. It's harmless. Goes away after a flush or two.

mike

I will flush it a few more times when necessary and see if it goes away. I can't believe BMW uses a product (hose etc) in a brake system that can be solvated by the brake fluid. It is not the only bike that uses DOT 4 Fluid ?

Thanks for the discussion

toooldtocare · Aug 17, 2014

From the Ducati world some reading material.

http://ducati1199.com/mechanical-technical/3322-black-brake-fluid.html

http://www.ducati.ms/forums/56-superbikes/196801-black-clutch-fluid.html

http://www.ducati.ms/forums/138-streetfighter/182841-dark-rear-brake-fluid.html.

http://www.899panigale.org/forum/899-panigale-general-discussion/9097-black-brake-fluid.html.

There are more out there.

racer7 · Sep 9, 2014

A couple things are certain- if the aggressive solvent nature of brake fluid is pulling stuff out of that line it is
1) Contamination of the fluid by simple definition and
2) Not helping the life of the line either. Any solvent attack on a uniformly formulated line will continue at some rate.

Sounds like defective tube to me- time to get a new supplier even if it doesn't cause immediate failure. Really no excuse for stuff like that to happen. Doesn't on all the other BMWs in my garage.

pauls1150 · Sep 10, 2014

I agree very strongly. Even if it's just one section of hose, it shouldn't be happening.

Even after reading all the Ducati links (and thanks for the extra and relevant info), I still believe it's an issue that shouldn't be ignored. "Heated" fluid has certainly degraded, but previous posters have inferred (but not positively stated) that the location of the master cylinder & hoses/etc. doesn't seem to be a culprit with the twins.

Consider how many vehicles - of any type - are out there on the road (and in the air) with hydraulic brakes. After gleaning so much experience, how could any manufacturer be so nonchalant about this? (Achleneiber, vunce again ze Amerikans are mistreating, und efen criticizing, our bikes!)

akbeemer · Oct 18, 2014

This came out of Annie's 2014 F800GS with 7666 miles on it. It seems we still do not have a firm reason as to why this is happening. I put Speed Bleeders on the bike so it is a simple job to do, and I guess that is a good thing.

weschmann · Oct 21, 2014

I've now rode 16,300 miles on the original brake fluid, which is the same color as in the last picture, with absolutely no issues. Just finished riding through the streams of Tennessee during the RibFest in Centerville, and look forward to another 3,000 miles before my first annual fluid flush, so at least for me, the fluid color has been a complete non-issue. YRMV........

akbeemer · Oct 21, 2014

weschmann said:
I've now rode 16,300 miles on the original brake fluid, which is the same color as in the last picture, with absolutely no issues. Just finished riding through the streams of Tennessee during the RibFest in Centerville, and look forward to another 3,000 miles before my first annual fluid flush, so at least for me, the fluid color has been a complete non-issue. YRMV........

You shouldn't expect to see an issue now. Any damage that contaminated brake fluid will cause will likely occur over a long period of time. It's much like saying I've been smoking for 5 years and I don't have a cough. Flushing the rear fluid is a very simple job and can be done in 15-20 minutes. You may never see any problems from riding with with contaminated fluid, but it makes no sense to me.

Rear Brake Fluid - 2014 F800GT

Old Rider - OK Mechanic

Right2Repair

MOA #24991, south of Los Angeles

Active member

Kawa Afterthought

3 Red Bricks

Active member

3 Red Bricks

MOA #24991, south of Los Angeles

MOA #24991, south of Los Angeles

New member

Active member

MOA #24991, south of Los Angeles

Old Rider - OK Mechanic

Active member

New member

MOA #24991, south of Los Angeles

SURVIVOR

Attachments

Kawa Afterthought

SURVIVOR

Similar threads