had new pressure plate and disk put in separator clutch since old one slipped, had heat cracks, and was worn out. can not get the lever to stay in the engaged position, adjusted linkage so lever does not bottom out in slot but then there is not enough pressure to keep the clutch engaged, put more pressure on clutch then the lever bottoms out and bounces back, clutch does snap over center, if i push on the clutch, it does snap over center really good. also the lever does not always stay up, it will fall down and then the plate contacts the disk, what can help this, and what is the adjustment for the clutch is it in the linkage or the clutch itself?