i have 99 2.0 non-turbo gs with hydro clutch and while at work i noticed i started having difficulty shifting into gears. i pull over and check the clutch fluid to find that it is empty so i filled it up and there wasnt anymore problems that night. the next morning however when i went to start her up there was barely any pressure on the clutch pedal but she still started up just fine and when i tried shifting into reverse there was resistance and the car started to move a tiny bit, the same happened with first gear. i can manage to shift into gear but it is difficult, there is no grinding noise when i do so. my best guess is to bleed the lines because air got into them. i just need to know what else might cause this to happen

 

replace the slave and master cylinders