I think my thread got hijacked while waiting for my master cylinder rebuild kit to arrive i guess i should also address the slave cylinder… do i need to replace it, or just re-seal it?
I would say that you likely need to replace the
slave cylinder - and don't bother trying to replace just the seal.
The ST1300 clutch slave cylinders seem to be going bad pretty regularly these days (
the bikes are all getting to be 15-20 years old) and they get pretty grimy and gummy up in there and some have shown corrosion as well. Mine, and I think that every single slave cylinder that others have replaced, has come out pretty badly damaged by age, engine heat, road muck, and dried-up hydraulic fluid (really it is just brake fluid). All of this just ruins the seals and seems to corrode the pistons and the cylinder bore itself as well - so replacing just the seals would be false economy.
My advice is, don't mess with it - just replace the whole thing with a new one. The cost difference between a rebuild kit (new seals etc.) and a whole new cylinder is minimal.
As for the
master cylinder (i.e. the control end of the clutch "circuit" - the one mounted on the handlebars), well, I am not sure that anyone has found that they ever seem to fail - but perhaps they do.
The point is that the
master cylinder lives in a much cooler and cleaner environment - and so, while there is no harm in replacing the seals, it is much more likely that your problem is the
slave cylinder than the master, from what people on this forum have experienced.