i have a '73 and i've replaced the clutch slave several times. it will drive good and strong for about an hour then the piston is forced all the way forward, sometimes nearly out perma-clutching (forcing the yoke forward, jammed) until i can get under there to unbolt it. even after removal from the line the piston wont go back into the unit. i now keep an extra slave with tools in the car just in case. good thing they are just $12 a pop. is there an adjustment i am missing to lessen the pressure?

i believe i have the non-adjustable version. thoughts?

Is it that the push rod is too short?? --You could make a slightly longer push rod. Simply cut the head off a suitable dia. bolt and round off the ends. I have done this.

i'll look into that, thanks!

Did this problem just pop up out of nowhere after years and many miles on the same clutch?

I presume it started after you change the slave cylinder?

It sounds like what olzed said. If the pushrod is too short the slave cylinder travel will "try" to compensate by moving further down the cylinder, but in turn litterally spitting out the piston in the process.

Try pushing the clutch fork and push rod back into the slave cylinder. It should go approximatly 10mm for a new clutch, older worn clutches will be less. If you can get 20mm of travel, you know it too short.

This problem can also be caused by mis matching throw out bearing collars and pressure plates. Common when people change transmissions and think the collar goes with the transmission. It doesn't seem to be the problem here though.

Chas