clutch pressure prob -- please help

[tetsuo]

Ok, my clutch pedal loses most of the pressure (so I can't shift gears) after about 30 minutes of driving (actually now only about 10 minutes, getting worse!). I have to pump the clutch several times rapidly and then it builds up again. Well I know there's air in there but help me tackle this one.

The strange thing is I just got done replacing the master AND the slave clyinders.

The bolts that I have changed are all secured, there are no leaks (that I can see), and the fluid level doesn't seem to be changing.

I believe I bled it correctly, I bled it twice and both times it ran fine (with full pressure) for several days... and then the problem comes back. Unless... I missed some air in there and they crept back after those days ??

I'm at a real loss here. Trying to solve it, I'm wondering:

1) what exactly is pumping the clutch do? Does it alleviate air in the system?if not, how does it build back pressure?

2) I'm wondering if it losses pressure a lot quicker on the freeway(because it feels that way). Does a clutch that's engaged change the state of the fluid system?

Thanks in advance!

[180fan]

you've got air bubbles. bleed it properly and the bubbles will go away.

[SeanC]

did you properly bench bleed the master? sounds like thats your problem.