Fiat is replacing the Clutch Slave Cylinder of all earlier delivered Punto. I came to know about this through punto google group. What is a clutch slave cylinder?
A clutch slave cylinder is a device used in the hydraulic clutch system, this item is mounted in the transmission, either on the outside, or in the inside.
If it is mounted on the outside, it is usually attached to the manual transmission by two bolts, the clutch slave cylinder has a rod that extends out every time hydraulic pressure is applied to it by the clutch master cylinder ( you operate this part every time you push on the clutch pedal). The rod that extends out makes contact with the clutch fork, in this design the clutch fork is the one who activates the clutch pressure plate. What are the symptoms of a bad clutch slave cylinder?
Usually when you have a bad clutch slave cylinder you know it right away, because since it is a hydraulic part, once a seal inside the slave cylinder gets bad, it will start leaking fluid, at the same time, because the seal is not sealing properly, it will allow air inside the system, causing your clutch pedal to feel soft and spongy.
When a clutch pedal feels that way, it is an indication of air in the system, and when this happens, it makes it hard to operate the clutch properly because it engages even with your foot almost all the way to the floor, at times you may not even be able to place your car or truck in gear due to this problem.
NOTE: A bad clutch master cylinder will have similar symptoms, make sure that you look closely at each one of these items to determine which one is the problem ( the one malfunctioning is the one leaking fluid ).
Source - howstuffworks