Inconsistent clutch stroke
 

Ok so this is not subaru related before we begin. Mate has a 99 triton 4x4 ute. When driving it the clutch has a normal amount of stroke at the pedal like most cars, however when parked on a hill when you go to take off the clutch all of a sudden is about half its normal stroke and the bite point is almost at the firewall. The clutch lines have been bled multiple times thinking it was air but it has not fixed the problem. Has anyone ever experienced something like this or know what the cause could be?

Yeah.

What usually happens (on anything with a hydraulic clutch) is when the pedal is up there is very little stopping the slave cylinder being compressed. ie; the weight of the bearing, fork, pushrod etc can slowly push the piston back into the slave and fluid back to the master cylinder. There is usually a very light spring inside the cylinder but it's not enough to hold the weight of those components out if you're on a slope. Sometimes there is an external spring (or you could add one) to minimise it. Not too strong or it'll load the clutch bearing prematurely.

Do not let anyone 'fix' it by adjusting the master cylinder pushrod. If the master cylinder pushrod has no freeplay the port remains closed and the fluid cannot return. It may temporarily solve the issue but as the clutch wears it'll slip prematurely.

Or......

There is excessive crankshaft end float, worn thrusts causing it.

Another clutch issue - small, but a bit annoying when at the track. I initially thought it was hot clutch fluid, but it's definitely not as i was able to reproduce the problem today.

Basically when driving hard and using the clutch vigorously, the clutch pedal changes, and feels as if it's almost gone, Like you have a lack of fluid and can barely change gear. The pedal doesn't come back like it normally would. As soon as you back off it's all good again.

Not sure if clutch or slave cylinder, clutch is about 2000km old.

Issue seems to have appeared since 6 speed conversion. Using 6 speed flywheel/clutch. Heaps of fluid in the reservoir. No leaks to be seen, and is fine when driving normally.

Do I need a 6 speed/STI clutch cylinder?