Hello, I have a 97 gmc sierra with a manual tranny. My problem is that when it gets cold the clutch pedal goes all the way to the floor. then I have to sit and pump the clutch pedal until it pumps up. on inspection I have found a bunch of black sludge in the clutch master cylinder. My question is if I Bleed out all of the Sludge will that help or do I need to replace the master and slave cylinders like the guy at the shop said?