Ducati Sporting Club UK > Model Specific - Discussion, Technical Problems and Help > 998 / 996 / 916 / 748 > Mucky Clutch Fluid

[Godders]

Should I be concerned that my clutch fluid takes on a nasty grey colour after only a few miles even though I've flushed repeatedly, have no leaks and original hoses, cylinder etc? There's no obvious degradation to the clutch performance but as an engineer I get nervous with dirty hydraulic fluid. Good to meet some of you on my first visit to John Henrys in Findon last Sunday - hope to meet more throughout the coming year.

Dave

[Rushjob]

Don't worry....they all do that!

[simonducati]

Originally posted by Godders
Should I be concerned that my clutch fluid takes on a nasty grey colour after only a few miles even though I've flushed repeatedly, have no leaks and original hoses, cylinder etc? There's no obvious degradation to the clutch performance but as an engineer I get nervous with dirty hydraulic fluid. Good to meet some of you on my first visit to John Henrys in Findon last Sunday - hope to meet more throughout the coming year.

Dave

[simonducati]

Im a new ducati rider and I had that problem to.
Take of you slave cylinder and see if your push rod is spinning, if it is that could be the problem, when activating the clutch your slave cylinder component mite be spinning and warring the black o-ring, making the fluid black. Its worth a look don’t you think ?

That was my problem and now my fluid stay’s clean .

[ali]

I've never had a duke that didn't do this after a couple of weeks. I tend to flush it every 4-6 months and it works fine, so I shouldn't be too concerned unless you start to lose clutch pressure.

Cheers,

ali

[Road Runner]

They all do it there have been many posts on this in the past. I can change the fluid on my 996 go for a quick blast and when I get home the fluid has gone much darker. Clutch still works fine..

[Walenut]

You could check the rubber boot that sits between the slave cylinder and the crank case (visible when the sprocket cover and the slave cylinder have been removed) its suppose to stop dirty chain lube getting into the slave cylinder and contaminating the brake fluid but is usually worn through by the chain in a couple of thousand miles.

If you are an engineer perhaps you could design us a version that works

[Edited on 19-1-2005 by S.P]

[antonye]

Do a search for Shazaam's posts - he explains it all.

[spinoli1]

Hi Godders,

I got ****ed-off with the clutch fluid going black, and set about sorting it - without success.

However, I can list some things that are not the cause of it:

1. Standard slave cylinder - I've replaced this twice with aftermarket cylinders, very carefully installed - no improvement.

2. Master cylinder reservoir - swapped this for a different make - no joy.

3. Pipe from reservoir to master cylinder - replaced with aftermarket fuel line - not guilty

4. Bearing in clutch pressure plate, seized causing push-rod to spin - nope.

5. Gunge from chain getting through rubber seal/gaiter thingy - replaced rubber whatsit, cleaned chain scrupulously, lubed chain very lightly, replaced fr sprcket, cleaned drive shaft area carefully - fluid black within 80 miles.

It has been suggested that the piston within the master cylinder is either not anodized and/or made from a low grade alloy that oxidises or reacts with the hydraulic fluid, causing it to darken. Seems a bit daft for Brembo to make such an error - but these are Italians we're talking about.

I find that after about 6 months/2,000 miles, the darkened fluid becomes susceptible to heat and clutch pressure fades - needing a system flush and bleed.

Otherwise, it is not a problem.

Still bugs me though. Better get a radial master cylinder.

Spinoli

[Shazaam!]

Over a year ago I sent a request for technical information via their website Technical Contact Form.

http://www.ducati.com/contact_us.jht...echnical.jhtml

Here's what I asked:

Myself, and a number of other Ducati owners are tired of all the speculation and would like a definitive answer to the following:

1.) Why does the clutch fluid (and not the brake fluid) turn black in color on Ducati motorcycles?

2.) What is the solution to prevent it, and why hasn't Ducati done so?

No answer ...

The answer lies in the kind of hydraulic fluid that you use.



The above picture shows fluid that had been in my 916 for two years after I changed to an aftermarket slave cylinder. Everything else except the system high-point bleeder (arrow in the picture) is stock. I used Valvoline SynPower Dot 3/4 fluid - Part No. 057 (boiling points: dry 513ºF, wet 333ºF.) Other owners have reported similar success with ATE Super Blue fluid.

See ...

http://ducatisportingclub.com/contro...d.php?tid=7924

Maybe the color change is Ducati’s way of reminding us to change our brake fluid every year or so. That’s the answer Ducati should have sent to me.