I've recently changed my clutch setup to ACT stage 1 on my non-turbo. Changed the pilot bearing, throw-out bearing, greased everything with molybdenum-based. Did not replace either the slave or master cylinder, ill-advised I know. Flushed the old clutch fluid, bled the new fluid and got it running great.

I drove it without a hitch for about two days. It shifted great, no weird symptoms whatsoever. Suddenly, when shifting into neutral, the pedal sticks to the floor and doesn't come back up. I coast into a nearby parking lot and pop the hood to diagnose. The slave cylinder had snapped!

I searched around the forum to try and find the cause, thinking it might have overextended itself due to a mistake in the hydraulics, or just broke due to old age. Today I looked into the clutch fork as a possibility and it seems like it's stuck. It won't budge at all when I try to actuate it by hand.

Has anyone experienced a problem like this? My theory now is that the clutch fork got stuck (pivot ball?) and the slave cylinder broke itself trying to force against it. Is this plausible?

 

With the amount of pressure it takes more press in the pressure plate you are not moving the fork by hand.

 

This occurred to me; I'm going to install a new slave and see if I can hydraulic the fork still. If it doesn't budge then, I'll resort to tearing the transmission down to investigate further...

 

The other possibility is the piston got jammed up inside the slave bore and simply broke it off. With hydraulic pressure, there is much more pressure there than seems possible. Also, I would find it unlikely the fork seized up and caused that. You would more than likely bent the fork in half first, before breaking the slave.

 

with the extra pressure of the new clutch it's possible that the old slave just couldn't handle the spring tension of the pressure plate.
Looking at the inside of that old slave it looks like it would have given up anyways.
Good advice would be to replace the whole hydraulic system..master,slave and line.

 

If you also look at the broken off bit, it's rusted through. It was bound to break at some point. It has been cracked for some time.

 

my butt has had a slight crack ..for about 50 years now..so I think it is about to give up too...lol!..it emits funny noises at low speed...

 

as long as you don't have any rusty residue, you should be fine

 

more likely the clutch fork pivot ball broke then the slave overextended and broke under the cocked pressure.