Funny clutch Problem

Hi all

So this weekend we went out for a ride through the cederberg and my clutch started acting up. It will loose pressure almost like it has got air in the system. Pump it and the pressure is back. First thought its the slave leaking at the bottom. I stop at the petrol station to fill up and bend down and inspect the slave and its dry. Check if its leaking at the master and its also dry. I carry on riding because its already dark and need to get to my overnight. Next morning i open up the master to find the fluid level still on its level. So my thoughts are with the mileage at 65k its probably time for a clutch master kit? Im thinking the pressure seal that keeps the pressure in the system is just worked out to the point where it is leaking fluid just a litte fluid past to drop pressure in the system. Its not leaking out at the master yet so think its an easy fix. Im taking off both master and slave tonight to see if i cant see anything funny.

Though ill asked if any of guys ever had this happen?

Thanks in advance.