hi guys common problem this, more than likely its the cluctch master cylinder, once it has dropped to the floor once, it will only get worse and could get to the stage where it will not come back up, its about 2hour+ job if all goes where, maybe worth a call to vw if yours cars are just out of warrany.
I work in a vw and audi dealership. Anymore questions i be happy to answer them.
gary