Rusty Shackleford

i jsut rebuilt my clutch master cyclinder and now it makes a cracking noise when pushing in the pedal.. and somtimes like maybe once a month a hard time putting it in reverse but i pull the cluthc out half way and it puts in.. and when i have the clutch out and u pop the hood u hear this not loud but not quite crunching noise like the car is grinding sand...whats could that be??