Intermittent Clutch Problem?

Took the 348 out for a spin on a rather cool Florida day. Drove about 25 miles with no shifts, then pushed the clutch down and noticed it engaged much closer to the floor than before.

My first thought was a leak in the slave cylinder, but after cautiously depressing the clutch several times afterward, the pedal seemed to lose its slack and become firm again. I noticed that during this period, I could "pump" the clutch a few inches and it would firm up.

Drove for another hour and had zero issues; pedal is tight from rest all the way to the floor.

Any guesses from the tech experts as to how this situation could occur? Impending problem, or maybe air? Something to do with the cooler weather? Something in the line?

I'm leaning toward air in the line, but after 8 months I can't figure out why this would appear suddenly, then vanish again.

Don't see any fluid anywhere, and I have yet to check the resivoir.

Thanks.

 

Just bumping my own thread to provide an answer in case others have a similar problem.

Was backing up and had my foot on the clutch, kinda mindlessly holding it in while chatting on my phone. After about 15 sec, I hung up and started to release the pedal when the clutch dis-engaged almost immediately. I slipped it into neutral, pumped the clutch pedal and all was normal again, but I didn't want to tempt fate by holding the pedal down.

Not being one to gamble, I took a short test drive and confirmed a very small drip of fluid on the inspection plate. I managed to limp home and garage her for weekend diagnosis.

Pulled the clutch off yesterday and the throwout bearing does appear to be leaking. Think I had a very slow leak, not enough to drip out at first, but enough to slowly lose pressure if I held the pedal to the floor.

For those keeping score, this was 3 months after the first sign of trouble.