Hello to all of you,

For the last few months I have been working on my 750 Paso and I’m facing an issue now for which I’m in need of some advice. It’s about the clutch master cylinder, which I’m overhauling. Or better, trying to overhaul . . .

When taking out the piston I expected an external circlip keeping the o-ring in its place. Just as with the front brake master cylinder, which I overhauled without any problem. To my surprise however I encountered a steel ring instead. Then I checked the replacement kit (Yeah, I know. Wrong order ) and there is also a steel ring. See pictures. It seems a strange construction to me, because how should such a ring keep the o-ring in its place? Just by clasping?

My question is: how to take out the old ring? It’s really stuck and also having it sitting in penetrating oil for several days is not helping getting it loose. Another strange thing is, the ring seems to be mounted in a slot. When asking whether he knew how to take it out, our fellow ducatipaso.org member Frank sent me this Youtube video with a 750 Monster master cylinder in which at the end (5:50 minutes) the ring comes out very easily. https://youtu.be/NjKaRd7-KWo

Is this the same construction as with a Paso (in other words: does it also have slot?) Has anybody got experience with this topic with a Paso? Thanks for helping me out!

Best regards, Ronald

Have a look at this video although not this type if you can grab or lock onto the inner plunger / seal as it is being replaced and tug it out it should bring the ring out with it. I hasten to add this is just a suggestion as I have not actually re furbished a 750 unit but I have on an early BMW K100.

This is an extract regarding a similar type of Brembo cylinder which is an alternative to tugging it out with grips

"" 4. With all external parts off you're going to see the inner metal with a small hemispherical ring in it when you look inside the fluid line side.

5. Time for a fine punch and rubber mallet. I didn't have a punch so I took a large nail and ground the point smooth and round. A couple of light to medium taps, and the little bugger should pop right out. ""

Regarding the video also have a look at his brake bleeding videos in his video list as they are quite informative.

https://www.youtube.com/watch?v=njKRhPwHOaM

I left the rubber seal /boot thing in place, rubber lubed the whole thing and pulled the piston assy out thru the wee push rod hole in the boot ( to be fair it stretched way further than I expected ) , and using the tool for putting rubber rings on lambs nut sacks , I spread the rubber boot open again, lubed it up and fitted the new piston assy