i already searched and havent found anything like my problem yet.
I dont see any leaks yet and the slave cylinder is only 4 month old

when i first turn my car on my clutch pedal feels weak. i always let my car warm up for 15 mins before i drive it. Once i go riding around for about 1-2 miles the clutch pedal will get stiff again. very weird.

 

check your fluid. rebleed. sounds like the fluid is getting warm an exspanding.

 

ok.
my fluid is full but i will try rebleeding