Clutch throw out bearing issue?

My 91 Testarossa runs and shifts well, but on a long drive yesterday, once the car got fully warm, I noticed that when I pushed the clutch in all the way while shifting, the clutch pedal would hesitate for a moment before it started pressing back against my foot to release the clutch. It all almost feels as if the TOB wants to seize in the depressed position momentarily.

When the car cooled off, the clutch returned to normal, until the engine got hot again on the return drive. The pedal always comes back, but it makes downshifting a lot harder to do smoothly.

Car has 60,000 km, runs well otherwise and the clutch does not slip.

Might it be the TOB, or the slave cylinder? Any diagnosis hints? It was about 38c here when I drove it, so a fair bit hotter than when I usually drive it.

 

Thanks, I will try that this week and see if it makes a difference; it is just that air usually manifests itself as the clutch not disengaging fully, rather than it sticking.

 

Interesting, I never considered that. I recall seeing a kink in the short steel hose which connects to the slave cylinder on the clutch bell housing. Odd that it would only act up when the engine is warm. Something I will check tomorrow.