Some hydraulic clutch system problems Options

[Coomer]

My car has been driving me nuts lately. For a long time, I've had some troubles shifting into first gear when I'm stopped. Sometimes I'd have to let the clutch pedal out and then push it in again to get into first when stopped. I replaced the slave cylinder, and it made things slightly better.

Now though, the problem is worse. I can't get into first very easily again, most often after the car has warmed up. Also, gear shifts are much more notchy, and I have to pause when shifting from first to second because it's so bad.

Today I adjusted the rod on the master cylinder so that it's pushing the piston as far as it can, but it didn't really make a difference. I also bled the clutch system and it made no difference.

I figure it's probably my master cylinder. I have no leaks anywhere in the system.

My question is, how exactly does a master cylinder fail? Do the rubber seals deteriorate so that fluid can get by the piston as it's pushed in? Does water/contamination get into the system over the time, rusting the cylinder walls so that there's a small gap where fluid can get through? Keep in mind that I have absolutely no leaks anywhere in the sytem.

And if my master cylinder is bad, should I get a cheaper replacement unit from somewhere like Autozone, or should I go for an OEM Toyota one?

Also, my problems get worse as the car warms up. Could the fluid be boiling from slave cylinder or the hard line being close to the header?

Also, do you think a braided stainless steel clutch line would help? Does anyone know if a MR2 or Supra clutch line could fit our cars?

[Coomer]

What's odd is that if I hold my foot down with moderate pressure and hold it there, it won't slowly sink at all. Also, I can put the car in gear and hold the clutch in for a long time and it won't stall or do anything.