It’s the brake fluid. The above picture shows fluid that’s been in there since August 2001 when I changed to an Evoluzione Cyclesports slave cylinder. I used Valvoline SynPower Dot 3/4 fluid - Part No. 057 (boiling points: dry 513ºF, wet 333ºF.) Everything else is stock.

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

Mav I tried your idea and a rubber boot thing popped out of the reservoir :o

Have I ****ed the master cylinder?

Have you been trying to bleed it with that rubber thing in the reservoir? That could be your problem!!

Dunno mate, emptied the master cylinder. started pumping brake fluid thru the slave cylinder, next thing i know this rubber thing pops out! :o
There's no air in the system, I've put fresh fluid in and bled til no more air, but still no bloody pressure :( :(


Deffo tempted by that ZX-10R now

Assuming its bled correctly then perhaps its something like a proken push rod thats causing the lack of pressure.

When you pull the lever can you hear anything happening down by the slave cylinder? On my bike i can hear the piston move if it quiet.

Take out the three bolts holding the slave cylinder to the engine, get the rubber dust seal out of the way and then gently pull the lever and you should be able to see the piston moving. Dont pull to hard or too far or the piston will pop out and you'll have to start all over again!!

Re the rubber thing, when you take the cap off you should see this soft circular rubber thing in there. Take that out before you try any bleeding.

Can't hear anything, there is no lever pressure whatsoever! I can hear a swishing sound from near the lever when I pull it

Could be that there's air trapped in the feed pipe from the reservoir to the master cylinder.
As the bore of this pipe is quite small and there is no pressure in it, it can be difficult to bleed the air from it.
The quick answer to the problem is the " Easibleed " or similar where you are pushing the fluid through from the reservoir using air pressure.
If you don't have one of those, try this.......
The technique I use to get rid of it is to half fill the reservoir, then every 5 seconds or so, move the lever a tiny amount, perhaps only 10mm of movement at the tip.
As you do this, look into the reservoir & you should see a small bubble of air appear from the hole at the bottom of the reservoir.
Slowly but surely, you willl bleed out any air in the feed pipe until you have only brakefluid in the tube to the master cylinder at which point you will notice a slight change in feel to the lever.
From then on, bleed the clutch circuit as normal.
This is a really frustrating technique but after 5 minutes or so you should be well on the way.
Don't be tempted to use bigger movements as all you will do is force the air back down towards the master cylinder putting you back to square 1.
Enjoy!
Andy

Basically what I did was use a syringe to push fluid thru the slave and into the master - the master is now full (but I dunno what to do with this rubber boot thing) and still no pressure!

The slave cylinder looked REALLY manky when I took it off to inspect it - but it was working before i tried to bleed the clutch, so I'm at a loss now :(

Heres a pic of the rubber thing

dj just explain to us how you are bleeding the clutch? are you pumping the lever and then undoing the bleed nipple and nipping it back up before letting go of the lever?

That rubber thingy is a folded rubber diaphragm that allows the level of the fluid in the reservoir to change without creating a change in reservoir pressure that would prevent proper master cylinder function. It’s main function is to prevent the hydraulic fluid from absorbing moisture from the air.

It’s supposed to be installed with the rubber part folded up into the cap and the reservoir filled.

Each time you pull the clutch or brake lever, you pump some fluid out of the reservoir, each time you release the lever, the fluid flows back into the reservoir. A little hole in the reservoir cap lets air in and out to equalize the pressure in the reservoir, but without the diaphragm the fluid will absorb moisture from humid air. As the fluid absorbs moisture, it’s boiling point drops and vapor bubbles develop that cause brake fade. Obviously fade isn’t an issue with clutches but the moisture in the fluid will still corrode metal parts that come in contact with it.

So like any diaphragm, you don’t really need to put it in, but there may come a point when you wish you did.:lol: