phunk

the pedal is probably getting stiff again from you building pressure in the system by using the clutch, its probably not temperature related... i think youre just eventually building up pressure and when the car sits overnight its gone. when i did my upgraded CSC with stainless lines for my OSGiken clutch, i had the same exact thing you are describing happen to me. It was because when I bleed the system I didnt use a compatible brake fluid... the mixture turned into a nasty gray goop that didnt hold pressure. After pumping the pedal a ton it would work normal for a while, but the pressure would fade if it sat. It took massive amounts of bleeding to finally flush it all through.

That was just my personal cause. If nobody has added or mixed in fluid into your system to cause the same problem I had, then either the seals in your master are bad, or your slave is bad/leaking. Its a very simple system, the clutch. It works just like brakes. The only way temperature is going to effect the hydraulic part of the system is if you overheat/boil the fluid... so I believe you have a pressure leak in one of the two components I mentioned.

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