SIP Hydraulic clutch spares

My SIP hydraulic clutch started acting funny and once I removed the clutch cover I found out why. The ball bearing pressure plate was toast and all the ball bearings spilled out over the floor. Something got caught in between the pressure plate and the actuating piston, so that’s badly scored in circles too. But the clutch cover seems fine and the piston still moves without leaking…

I now need to buy a new ball bearing plate and the metal plunger that sits in the clutch cover BUT I can’t seem to figure out what I need from the info on the shopping site.

This looks like the pressure plate but it says NOT FOR USE WITH HYDRAULIC CLUTCHES:

I am pretty sure this is the plunger:


Ive had the same problem with mine. I dont think the piston gets any free play and keeps pressure on the ballrace at all times. albeit very little. The ballrace looks similar to the rotax clutch release, it may not be from that but the dimensions are the same, and they run in an oil bath. My solution was to remove the piston and bore a blind hole in it with interference fit to take a pk brass plunger machined to length, and use a standard plate on the cosa clutch. It may seem long winded but a surefire and reliable solution. Alternatively, which I did first, was make up a new piston that is slightly longer but found you still need a bearing surface which the brass plunger does. Use pk plunger cos its longer and easier to machine. All the best.