HELP really wierd clutch issue

[393mach1]

i just bought a 91 explorer with a 5 speed. it drove great, no problems. i was driving home and after about 30 minutes of highway driving, i pushed the clutch in and it would not disengauge. i left it in gear and made it home and parked it. today i went out, and it worked perfectly fine without a problem. i pulled it in the garage and checked for clutch fluid leaks. there were none, everything looked great, so i bled the clutch fluid. it was pretty dark, but seemed ok. i bled it until nice new clear fluid came through. i took it for a test drive and everything was ok for abouit 1/2 mile, but then the clutch wouldn't disengauge. the petal went to the floor just like before, but the clutch was still engauged. i turned it off and put it in reverse and was going to start it in gear and drive home, but when i started it, the chutch was working perfectly again????? i really cant figure this one out. i found a few posts with the same problem, but none with a solution. i assume it has to be either the clutch master cylinder or the slave cylinder, but which one, and why? i dont mind doing one, but i don't want to do the wrong one and then have to do the other anyway. any advise is appriciated, thanks.

 

[Solojourney]

I have a 2000 sport that had a very similar problem a few weeks ago and I replaced the master cylinder which solved the problem. there were no leaks anywhere and a slave requires a tranny pull.
I bench bled the new master before installing it and finished with a complete bleed after installation to minimize any air in the system.
I may be wrong but I think a check valve may have been malfunctioning and dumping pressure back to the reservoir when the pedal was pushed. this would account for no leak and an erratic behavior such as your problem.
Hope this helps.
Mike

 

[Burns]

It seems like a master cylinder prob. I am on my second one now thank goodness for liketime warrenty.

 

[briwayjones]

It could be the throw-out bearing is going bad. Sounds like it's time for a new clutch, slave cylinder, throw-out bearing ect.

 

[393mach1]

thanks for the replies guys. i think i'm going to try the master cylinder since i don't have to drop the tranny to do it. i was really confused about where the fluid was going, but the check valve idea sounds right. it must be going back up into the reservoir. thanks again, i'll let you know how it works out.