The center of the clutch pressure plate has a double-sealed bearing. Every 20K or 5 years, I recommend replacing this bearing. One way to inspect the bearing is to put your finger in the center of the pressure plate and try to spin the bearing. If you feel any sticking, replace the bearing. If the bearing seizes, it will destroy the clutch pushrod, and possibly the transmission needle-bearings. This bearing is an interference fit in the pressure plate, and must be installed and removed with a socket extension and a mallet.
This bearing also fits the alternator cover to hold the end of the crankshaft and the idler wheels for belts on desmodues and pre-testastratta desmoquattros.