I had a new clutch put in my 95 f150 with a 300 back around christmas. everything from the slave cylinder in was replaced. Theres only about 3,000 miles on the clutch. Anyway about 2 weeks ago i went to take off and the clutch went about half way up and didnt come back up so i pulled it up with my foot, gave it some pumps then it was fine. every time since then the first time i start it it would let out right at the floor, wayy closer then before, but after shifting a couple times it went back to being ok. today i went out and it seemed to get worse till then over town it wont come back at all. Hardly no pressure at all. Its acting like it did the first time my clutch went out around christmas. Im thinking it may be the master cylinder since thats the only thing that hasent been replace. I cant see how it would be the clutch. Any suggestions? Thanks

 

Check the fluid...you may have a leak.

 

No leak and its filled with fluid.

 

I had the same problem, the pedal wouldn't return to its upper stop. I assumed this might have had something to do with the bent fingers on the pressure plate. I replaced the clutch, release bearing, and slave cyl because of the pressure plate, and when I went to bleed it all I couldn't get fluid to flow from the reservoir into the master cyl itself. Found out the piston seals (1-way boots like on an old hand water pump) had been exposed to motor oil and swelled to be too big to contract and let whatever's in the reservoir into the system. The vacuum that is maintained by this 2-way seal is what is keeping the pedal on the floor despite the master cylinder return spring. Here is how you can tell if this is your problem: Open the bleed screw and cover it with your finger. Have a buddy push the pedal down, and fluid should squirt out. Keep your finger there when he snaps it up (it must be moved up fast), and if after about 3 seconds there is still a vacuum on your finger then you have a master cyl piston seal that can't be bypassed for some reason. Otherwise, be sure there is no crap in the little hole that lets fluid out of the bottom of the reservoir and that the hole is aligned properly.

 

If you try to bleed the system does the fluid in the reservoir go down?