Experience with master cylinder rebuild?

[d3vi@nt]

Ah, the recall.  What is the piston made of?  If it is plastic Ducati has to fix it for free regardless of...well...anything.

The original was made with PPS (Polyphenylene Sulphide) and based on the documentation is light brown in color. The replacement is aluminum. The existing piston appears to be aluminum, same as the replacement. Seems they switched in later model years.


https://static.nhtsa.gov/odi/rcl/2017/RCSB-17V812-2711.pdf

[Howie]

In that case the piston can be used again.  The problem would be sourcing proper seals.  You might have some luck with other brands using that master.

[d3vi@nt]

Well... I'm puzzled.  I finally broke down and bought a used MC off of a '14 MTS (2010-13 MC were all superseded by '14).

And I've got the same problem. Rode fine for about 300 miles, then next to zero friction zone with clutch grabbing just a hair off the grip.

So I've replaced the slave with a new Oberon unit, replaced the MC. The only two remaining options I can see are that 1) the line has a pinhole somewhere, or 2) my technique somehow is leaving an air bubble somewhere/somehow.

Any other thoughts or suggestions?

[Speeddog]

The reservoir, the hose, the plastic fitting, and the rubber biscuit it fits into, all of those can leak air in and not leak fluid out.

[d3vi@nt]

The reservoir, the hose, the plastic fitting, and the rubber biscuit it fits into, all of those can leak air in and not leak fluid out.

Right. Those parts were all included with the MC, so I replaced the whole assembly. That's not to say the replacement parts can't be the issue, just not sure.