BLACK BRAKE FLUID

[Myke Rocks]

colour change

When the brake pads are changed, the fluid is pushed back into the reservoir as the pistons are retracted. This fluid at the working end of the system normally undergoes a colour change with time.
Who cares!
Myke

 

[JJH]

I think when fluid gets too hot it goes dark. JJH

 

[mechcanico lee]

Sounds like a logical conclusion; I shall go out and check mine in a little while!

Reading this with interest, can understand the colour leaching effect thing, but wouldnt the front do the same as it has a pipe from the res to the master cylinder also.
Could it be something to do with the heat that gets transfered into the fluid, the front fluid will get hotter as that makes more heat under braking, maybe the rear fluid goes darker as it stays cooler and doesnt exchange up the lines as much........i dont know ?? just some thoughts

A dont think it matters so much all the same.

 

[Greggers]

My take on it ...

Brake fluid is designed to operate at high temperatures, and to be honest, unless you're constantly riding the back brake the caliper itself shouldn't get so hot that it can transfer huge amount of heat to the fluid ...

I'd support the thought that there's an incompatibility between the fluid and the reservoir feed pipe which is causing the fluid to discolour by leeching pigment from the pipe material, maybe another example of BMW cutting costs.

I raised this at my 6k service and they changed the fluid (charged me too though!) which at this moment is quite dark, and certainly not the light honey colour of the front fluid. Maybe the next change will sort the 'problem' out if there's no more leeching.

TBH I'm not worried - the brake still works and doesn't feel spongy, but if I can be arsed I might change it for some dot 5.1 next time round.

Greg

 

[Lighty]

Found this with a search, but noticed yesterday that my clutch fluid has gone jet black, same colour as the lid
Havnt used the bike for a week, and Iam sure it wasnt like that last time.
Anyone decided on a cause bike only done 3K miles, not quite 1 year old yet.

Mines a 1200 btw

 

[StumpyFingers]

Found this with a search, but noticed yesterday that my clutch fluid has gone jet black, same colour as the lid
Havnt used the bike for a week, and Iam sure it wasnt like that last time.
Anyone decided on a cause bike only done 3K miles, not quite 1 year old yet.

Mines a 1200 btw

I had the rear brake fluid on my F800 go black, I was informed that it is normal and when the bike goes in for its first Annual service the fluids are changed and they stay the correct colour, so far mine have returned to normal.

 

[chas820]

I had this happen on mine when the bike had reached about 2000 mls,I also lost all braking.Vines sorted it under warranty but couldnt explain why it happened,they said it was common.I believe all they did was to replace the fluid and bleed.

 

[Shadwell]

I was just going to change my brake fluid and pads but thought i would read the relevant paragraphs in the haynes manual first. It says "all ABS models that have work done on the braking system that involves bleeding the system afterwards requires the use of the BMW diagnostic tester to restore braking action" therefore take it to a dealer.

I am happy how to change the liquid but why the diagnostic tester?

And as i am changing liquid, not flushing air out of the system is it still required?

Thanks, Shad

 

[Smythson]

Did mine a while back - didn't do any diagnostic stuff and they work just fine. I can only imagine this is a safety warning in case there has been air in the system?

 

[Shadwell]

Thanks for that mate, I'll go for it in the morning and see what happens))

 

[steve hughes]

Ive bled my rears twice , also once before a service, they were always better for the bleeding and no computer errors seen or advised. Its woth unscrewing the rear resevoir as this improves access , just make sure it remains upright !

 

[ADA]

Normal

Don't worry. 55,000km+. It is normal. It is leaching of the pipes colour into the fluid. I have never heard a problem of it, and I own a Bumble Bee. My second set of fluid has been black for the last 20,000km.
No wuz

 

[JWFr]

I don't believe this has been mentioned, but one of the quickest ways for turning hydraulic fluid black is heat. A warped disc, worn pads and heavy use can cause a huge heat build up in a short ( physically short) circuit like the rear set up on the twins.

 

[JJH]

Chech my post jjh