I am able to keep pressure for about a week or so. No clutch fluid leaks out, (I know this because I never have to top up the resevoir) also I am not exactly sure which cyclinder is which, one is internal (under the engine and the other is not) I changed the one that is not and I have assumed it is the slave. Can there be any other causes? I was told by my mechanic that it is a hyraulic problem and not a function problem... How big of a job is it to change the seals? (30 Minutes - 4 hours?) Thanks for your help.