yes it is possible.

Internal leaks around seals can result in the feeling you describe. It is not that bad a job to replace the M/C, no need to fully drain the reservoir, just down to the level that the clutch supply hose leads from. When putting in the new one, leave the bolts (2 bolts holding M/C to van) loose until you do up the metal clutch line. Also be sure the shaft that goes into the M/C goes in without binding and put a dab of grease on the tip of it.

The slave is a bit more of a job. Awkward access and sometimes difficult bleeding. See if there is any leakage in the boot. 

I have found that when they fail it is in colder weather. 

alistair

On 2011-10-07, at 3:19 PM, Jamie McMahon wrote:

> Is it possible for my clutch master cylinder or slave cylinder to be bad and not leak fluid? The clutch master cylinder was replaced a couple of years ago, slave cylinder probably about 30k on it. My clutch feels soft and sometimes goes right to the floor with little resistance but will pump back up. I have tried bleeding it and there is no air in the line. Everthing I have read indicates when these parts fail they leak. Any help would be appreciated.
> 
> Thanks
> Jamie
> 87 Vanagon GL
> 73 Westy