Clutch Master Cylinder

jfiore · Post by **jfiore** » Sat Apr 16, 2005 10:12 pm

Has anyone had any success in re-building the clutch master cylinder? Mine just died, and it seems like it was designed to throw away. If anyone knows how to remove the circular clip that holds the piston and seal in place, I would like to know how.

Has anyone tried replacing the clutch and/or brake master cylinders with ones from another type of bike? Again, any information would be greatly appreciated.

Post by **Skins** » Sat Apr 16, 2005 11:25 pm

Some years ago, my clutch master cylinder started to leak at the lever end. Can't remember all the details (too many drugs and loud motorcycles - nah, just kidding about the drugs), but I think the trouble was just the boot at that end, and I fabricated a new boot from a plastic cap of some sort that I had put aside for that kind of situation. It has worked fine for several years now, so I don't want to disturb it, but I seem to recall taking the whole thing apart, and cleaning things up with wet and dry paper, etc. One can make serviceable seals and boots to fit out of suitable material. Sounds like you just have to figure out how to take it apart.

jfiore · Post by **jfiore** » Sun Apr 17, 2005 11:15 am

That's the problem, Skins! The rubber dust boot and the piston assembly are held into the housing by a retaining ring that seats into a groove in the housing. The only hitch is that the ring is not a split ring, and I can't get a tool underneath it to pry it out, since it's an interference fit. It would have been nice if Brembo had used a simple snap ring, but they didn't.

If you could offer any suggestions on how to get the retaining ring out, they would be most appreciated.

Post by **Skins** » Sun Apr 17, 2005 8:14 pm

Well, I am loath to disturb the boot I made for the unit on my bike to examine the assembly, I'm afraid. I remember thinking 'I'll be lucky if this works' when I did it a few years ago. I'm even hesitant to say how happy I am that it has worked all these years, in case I tempt fate.

I've had a look at the diagram of the master cylinder in my Ducati Paso 750 Spare Parts Catalogue, but it's impossible to tell from that how the clip works. I had a quick look at the Brembo.com website - it looks very good, but you have to register to really get into it. You could try that.

Otherwise, I suggest adopting the attitude 'If that clip was put on there, it can be got off'. They can be very stubborn, those clips. Recently, one that's usually easy for me gave me heaps of trouble - I think it was on a carburetor.

You might have to use exactly the right tool - perhaps a really sharp knife point, and a very precise technique, with some force.

Dukem · Post by **Dukem** » Sat Jul 30, 2005 9:56 pm

Hi, if you buy a Brembo overhaul kit, it comes with a new piston, seals, dustboot and round clip. I prised the clip out with a screwdriver after cutting away the old dustboot, the clip and boot are both damaged on removal but is not a concern as new ones are supplied in the kit. Behind the round clip is a white plastic scraper seal and O-ring, all supplied in the kit. Bleeding the clutch can only be done by removing the handlebar and tilting at an angle to eliminate the air bubble from the banjo bolt and just gently pressing the handlever until the air bubbles are released.

jfiore · Post by **jfiore** » Mon Aug 01, 2005 2:25 am

Thanks for the advice. I've previously completed the rebuild and am happy with the results. The only unfortunate thing is that when prying out the retaining ring, the aluminum body of the MC is easily scratched. For anyone else who needs a Brembo rebuild kit for either the brake or clutch master cylinders, or new (NOS?)brake calipers, check out http://www.bevelheaven.com. Although they cater mostly to the older bevel-drive bikes, they carry many Brembo items that are the same as on the Paso.